Aberrant- Deviating from the ordinary, normal, or expected (Bechtel, 1995).

Abundismus- A type of Melanism in which the specimen is not completely black, but shows a change in the elements of the basic pattern as consequence of the number of isolated black spots or dots in the nonblack areas of the pattern (Peters, 1964).

Adaptation, biological- Alteration of structure or function to suit a particular environment (Bechtel, 1995).

Albinism- The heritable condition observed as the inability to form melanin in the skin and scales (Allaby, 1991).  Absence of pigment in animals usually pigmented; the state of having colorless chromatophores (Holmes, 1979).  Lacking pigment and therefore appearing pink or white (Mattison, 1986).  A genetic absence of tyrosinase (Bentley, 1982).  The appearance created by a lack of black pigment in the dermal and epidermal chromatophores (Barker, 2006).

Albino- Normal pigment is absent from the scales (Allaby, 1985).  The blood pigment hemoglobin is present and may result in pinkish specimens or specimens with red eyes (Mattison, 1991).  A commonly used term for Amelanistic.  (McEachern, 1991).  An organism with absent or deficient melanin (Bechtel, 1995).

Allele- A shortening of the term allelomorph; one of two or more forms of a gene arising by mutation and occupying the same relative position (locus) on the homologous chromosome; may be distinguished by their differing effects on the phenotype (Allaby, 1985).  Either of the two paired genes affecting an inherited trait (Bechtel, 1995).

Allophore- A cell or chromatophore containing red pigment in the skin of reptiles, amphibians, and fish (Peters, 1964; Holmes, 1979).

Amelanism- A term sometimes used instead of Amelanistic (McEachern, 1991).  The appearance resulting from a lack of melanin (Barker, 2006).

Amelanistic- The pigment melanin, which is responsible for black, brown, and yellow colors, is absent; specimens are pale in color, although they may have some color, especially red or pink, owing to the presence of other pigments (Mattison, 1991).   A single recessive mutation resulting in a lack of black pigment referred in both skin and eyes; bright red and orange predominate (McEachern, 1991).  Containing no melanin (Bechtel, 1995).  The appearance created by the lack of all Eumelanin and BCM (Barker, 2006).

Amino acid- Any of the subunit building blocks that are covalently linked to form proteins (Klug, 2003).  Organic compounds that are the building blocks of protein (Bechtel, 1995).

Anal scale- A single unpaired scale that covers the cloacal opening.  Although it may be regarded as the posteriormost scale in the series of ventrals, the anal scale is not included in counts of the ventral scales (Barker, 2006).

Anerythristic- Having a lack of red pigment and all red markings (Mattison, 1991).  A mutation that can be caused by two separate defective genes resulting in a lack of red and orange pigment; predominantly marked with grays but also black, brown, or yellow (McEachern, 1991).  An appearance that is without red; and appearance usually assumed to be the result of reduced or absent Erythrophore pigment production in the skin (Barker, 2006).

Angle of the jaw- The area on the lateral surface of the head positioned above the articulation of the upper and lower jaw bones, usually at the widest area across the head (Barker, 2006).

Anomaly- A deviation from the ordinary, normal, or expected (Bechtel, 1995).

Anterior- An anatomical direction meaning toward the front or toward the head (Barker, 2006).

Anterior prefrontals- Asingle pair of large plate-like prefrontals in contact with the internasals and in full contact along the midline (Barker, 2006).

Appearance- The perceived outward aspect of a snake resulting from the combination of its color and pattern.  Sometimes used as a synonym of phenotype (Barker, 2006).

Arboreal- Living in trees (Bechtel, 1995).

Axanthic- Frequently having a lack of yellow pigment; a term sometimes used instead of anerythristic, but not appropriately (McEachern, 1991).  In the descriptive sense, an appearance lacking the expected visual contributions from yellow or orange pigments (Barker, 2006).

Axanthism- Literally “without yellow.”  The absence of yellow or orange color (Barker, 2006). Absence of yellow pigment, or absent or deficient xanthophore pigment metabolism (Bechtel, 1995).

Azygous- Occurring singly; unpaired (Barker, 2006).

Backcrossing- Mating of an organism with a parent (Bechtel, 1995).

BCM- The acronym for black cellular material, an inclusive term to refer to all the chemical compounds of black pigment found in melanophores (Nicolaus, 2001).

Bilateral- Occurring on both sides of an organism (Bechtel, 1995).

Biochrome- A pigment produced in a chromatophore (Nicolaus, 2001).

Breed true- A phenotype for a trait is said to breed true if two parents with that phenotype produce offspring of that same phenotype exclusively.  In reference to a familial trait that has been reproduced through inbreeding / line breeding enough generations so that the offspring when bred together will produce offspring exhibiting the trait in question.

Carotene- A yellow skin pigment widely distributed in animals (Holmes, 1979).  Yellow pigment (Bentley, 1982).

Carotenoids- Fat-soluble pigments widely distributed in animals and including carotene and xanthophylls (Holmes, 1979).

Carotin- Same as carotene.

Character- An observable phenotypic attribute of an organism (Klug, 2003).

Chlorophane- A green chromophane (Barker, 2006).

Chromacyte- Any cell containing a pigment (Holmes, 1979).

Chromatophores- Pigment cells (Bechtel, 1995).  Cells in the skin that usually contain pigments of different colors (Bentley, 1982).  A colorless body in cytoplasm and developing onto a leucoplast, chloroplast, or chromoplast (Holmes, 1979).  Any cell that bears pigment and thereby plays a role in the overall color pattern of the animal (Peters, 1964).

Chromoblast- An undifferentiated pigment cell in an embryo (Barker, 2006).

Chromophane- Retinal pigment in lower vertebrates (Holmes, 1979).

Chromosome- Occurring in the nucleus of a cell (Allaby, 1985).  Composed mainly of DNA and basic protein, and bearing the genes being arranged in linear order (Holmes, 1979).  Chromosomes are arranged in pairs with the genes being arranged on the chromosome (Mattison, 1991).  The presence of homologous chromosomes is referred to as the diploid state (Allaby, 1991).  Nuclear inclusion containing genes arranged in linear sequence (Bechtel, 1995).

Circumoculars- The series of scales that rim the eye, including the preoculars, a single supracular, the postoculars, suboculars, and supralabials (Barker, 2006).

Cloaca- The common chamber in the body of reptiles and amphibians into which the reproductive, intestinal, and urinary ducts open (Cogger, 1992).  The external opening of the cloaca is termed the vent, anus, or cloacal opening (Barker, 2006).

Cloacae- Plural of cloaca (Barker, 2006).

Cloacal opening- The external opening of the cloaca; also termed the vent, or anus (Barker, 2006).

Codominant gene- Expression of heterozygous phenotype resulting in hybrid offspring that resemble both parents equally for a particular trait (Hartwell, 2004).  Condition in which the phenotypic effects of a gene’s alleles are fully and simultaneously expressed in the heterozygote (Klug, 2003).

Complete dominance- See dominant gene.

Crossing over- The exchange of chromosomal material (parts of chromosomal arms) between homologous chromosomes by breakage and reunion. The exchange of material between nonsister chromatids during meiosis is the basis of genetic recombination (Klug, 2003).  During meiosis, the breaking of one material and one paternal chromosome, resulting in the exchange of corresponding sections of DNA and the rejoining of the chromosome. This process can result in the exchange of alleles between chromosomes (Hartwell, 2004).  Compare recombination.

Cysteine- A nonessential amino acid (meaning that the body can synthesis it) important in the synthesis of pheomelanin (Barker, 2006).

Deoxyribonucleic acid (DNA)- A molecule containing the genetic information of all living cells (Bechtel, 1995).  A macromolecule usually consisting of antiparallel polynucleotide chains held together by hydrogen bonds, in which the sugar residues are deoxyribose.  The primary carrier of genetic information (Klug, 2003). The molecule of heredity that encodes genetic information (Hartwell, 2004).

Designer appearance- Popular term referring to the phenotype resulting from the selectivebreeding to combine two or more appearances, each caused by a different mutation (Barker, 2006).  See hybrid.

Dihybrid cross- Mating of individuals heterozygous for two separate inherited traits.

Dimorphism- Occurrence of two forms, distinct in color or other characteristic, among animals of the same species.

Diploid- Having two sets of chromosomes; the typical zygote arrangement of chromosomes(Holmes, 1979).  An individual with two chromosome sets in each cell, excluding the sexchromosome (Allaby, 1985).  See haploid.

Dominance series- Dominance relations of all possible pairs of alleles are arranged in order from most dominant to most recessive (Hartwell, 2004).

Dominant gene- The normal form of the gene that is usually denoted by an uppercase symbol (McEachern, 1991).  An allele that determines the phenotype of the heterozygote (Lincoln, 1990).  An allele that can determine the phenotype whether heterozygous or homozygous (Bechtel, 1995).

Dominant negative- Mechanism of dominance in which some alleles of genes encode subunits of multimers that block the activity of the sub units produced by wild type alleles (Hartwell, 2004).

Dominant suppression- A form of epistasis in which a dominant allele at one locus suppresses the effect of a dominant allele at another locus (Klug, 2003).

Dopa- 3, 4-dihydroxy-L-phenylalanine, an intermediate chemical in the synthesis of melanin (Bechtel, 1995).

Dorsal- Pertaining to the back; an anatomical direction meaning toward the back (Barker, 2006).  The top, back, or uppermost surface of an organism (Bechtel, 1995).

Dorsolateral- Pertaining to the area between the dorsal and lateral surfaces (Barker, 2006).

Dorsum- The upper surface or back of a python (Barker, 2006).

Ectopic expression- Gene expression that occurs out side the cell or tissue where the gene is normally expressed (Hartwell, 2004).

Ectothermic (Poikilothermic or cold-blooded)- Possessing no internal means for controlling body temperature (Bechtel, 1995).

Embryo- Organism in early stages of development, before it is physiologically independent (Bechtel, 1995).

Endothermic (Homeothermic or warm-blooded)- Having ability to maintain constant body temperature in different ambient temperatures (Bechtel, 1995).

Epistasis- The situation occurring when one allele of one gene obliterates the phenotypic expression of all other allelic alternatives of another gene (Suzuki, et al., 1986).  A gene interaction in which the affects of an allele at one gene hide the effect of alleles at another gene (Hartwell, 2004).  Nonreciprocal interaction between genes such that one gene interferes with or prevents the expression of another gene (Klug, 2003).

Erythrism- Having red skin and scales caused by a lack of black pigments (eumelanin), which allows the red pigment (pheomelanin) to dominate the color of the appearance (Allaby, 1991).  Abnormal or excessive amount of red coloring (Holmes, 1979).  The occurrence of unusual amounts of redness in an individual or population as compared to the normal pattern of the species (Peters, 1964).

Erythrochromism-  See erythrism.

Erythrocystic-  See erythrism.

Erythrophores- Reddish-purple pigment-bearing cells (Holmes, 1979).  Cells containing carotenes or yellow pigment(Bentley, 1982).  Xanthophores that appear red (Bechtel, 1985).

Erythrophore- Red chromatophore (Bechtel, 1985).

Eumelanin- A form of melanin that is black or dark brown (Mattison, 1986).  Black or brown melanin (Bechtel, 1985).  See phaeomelanin.

F1- Symbol denoting the first filial generation, being hybrids (offspring) arising from a first cross; successive generations arising from this one are denoted by F2, F3, etc.  The second filial generation is the progeny resulting from a cross of the F1 generation and the third filial generation is the progeny resulting from a cross of the F2generation ect. The symbol P1 denotes the parents of the F1 generation, and P2 denotes the grandparents (Holmes, 1979).

Familial trait- A trait transmitted through and expressed by members of a family (Klug, 2003).

Frontal- The area of the top of the head located between the supraocular scales; one of usually two flat plate-like scales on top of the head between the supraoculars (Barker, 2006).

Fundus- The bottom of a labial pit.  The fundus has a distinctly modified, nerve-rich epithelium (Barker, 2006).

Gamete- Haploid cells that fuse to form a zygote in sexual reproduction (Holmes, 1979).  A specialized haploid cell(sex cell) whose nucleus, and often cytoplasm, fuses with that of another gamete in the process of fertilization, thus forming a diploid zygote (Allaby, 1985).  In the case of ball pythons, a male gamete is termed a sperm or spermatozoon, and the female gamete is termed the oocyte or ovum (Barker, 2006).  Mature haploid egg or sperm (Bechtel, 1995).  See germ cell.

Gene- Unit of inheritance (DNA), carried on chromosomes (Bechtel, 1995).  The fundamental physical unit of heredity, whose existence can be confirmed by allelic variants and which occupies a specific chromosomal locus (Klug, 2003).  A unit heredity factor consisting of a short length of chromosome and having a particular effect on thephenotype (Barker, 2006).

Gene pool- Collectively, all of the alleles of all the genes in a population (Bechtel, 1995).

Genetics- Study of heredity (Bechtel, 1995).

Genetic linkage- See linkage.

Genials- The scales bordering and lining the mental groove (Barker, 2006).

Genome- The array of genes carried by an individual (Klug, 2003).  The sum total of geneticinformation in a particular cell or organism (Hartwell, 2004).

Genotype- Genetic constitution of an organism as opposed to its physical appearance (phenotype); the fundamental physical unit of heredity (Allaby, 1985).  Genetic constitution of an individual (Holmes, 1979).  Refers to the state of the genes, for example “homozygous for amelanism” or “heterozygous for striping” (McEachern, 1991).  Genetic makeup of an organism (Bechtel, 1995).  The actual alleles present in an individual (Hartwell, 2004).  See phenotype.

Germ cell- Mature haploid egg or sperm (Bechtel, 1995).  See gamete.

Gravid- Pregnant (Bechtel, 1995).

Guanine- Pale granules produced in the guanophore and usually having a pale color, or as iridescent crystals in the skin of reptiles contained in a chromatophore known as an iridocyte (Holmes, 1979).  See iridocyte.

Guanophore- A chromatophore containing guanine (Holmes, 1979).  Two general types of guanophores found in reptiles, amphibians, and fish are leucophores and iridophores (Hama, 1975).  See guanine, iridophores, and leucophores.

Gular- The underside of the head, the throat.  Gular scales are the scales on the throat, an area bounded by theinfralabial scales, genial scales, temporal scales, and paraventral series (Barker, 2006).

Habitat- Specific place within range in which an organism lives (Bechtel, 1995).

Haploid- Having the number of chromosomes characteristic of the gametes for the organism-the typical gamete number after meiosis (Holmes, 1979).  Having only one copy of each chromosome (McEachern, 1991). A haploid cell has only one chromosome set, and a haploid cells (Allaby, 1985).  Chromosome sets are often denoted by the symbol n (1n = haploid, 2n = diploid, 3n = triploid, etc.).  Ball pythons are diploid organisms (Barker, 2006).

Haploinsufficiency- A rare form of dominance in which an individual heterozygous for a wild type allele and a null allele shows an abnormal phenotype because the level of gene activity is not enough to produce a normal phenotype (Hartwell, 2004).

Hemoglobin- A red hemochrome pigment (Holmes, 1979).  Conjugated protein that binds molecular oxygen in a loose, easily reversible manner, and is used as a respiratory pigment in numerous reptiles; confined on the surface of specialized blood cells, the erythrocytes (Allaby, 1985).

Hereditary- Capable of being transmitted from generation to generation (Bechtel, 1995).  The way genes transmit biochemical, physical, and behavioral traits from parent to offspring (Hartwell, 2004).  Transmission of traits from one generation to another (Klug, 2003).

Herpetoculture- Breeding and husbandry of reptiles and amphibians (Bechtel, 1995).

Herpetology- Study of reptiles and amphibians (Bechtel, 1995).

Heterozygous- Also referred to as “het” or “hetero.”  Describes animals that appear to be normal (dominant genes) but carry a recessive gene (hidden gene) for some known characteristic; the recessive gene may be passed on to future generations (Mattison, 1991).  The heterozygous condition may be represented by the symbol Aa with the upper case “A” representing the dominant gene and the lower case “a” representing the recessive gene (McEachern, 1991).  Having nonidentical alleles for the trait in question (Bechtel, 1995).  Having different alleles on homologous chromosomes at the same locus (Barker, 2006).

Homologous- Corresponding in origin, structure, and position (Bechtel, 1995).  Genes or regulatory DNA sequences that are similar in different species because of a descent from a common ancestral sequence (Hartwell, 2004).

Homologous chromosomes- Chromosomes that contain identical linear sequences of genes; homologous chromosomes pair together during meiosis (Allaby, 1985).  Chromosomes that match in size, shape, and banding. A pair of chromosomes containing the same linear gene sequence, each derived from one parent (Hartwell, 2004).

Homologous genes- Genes determining the same character (Holmes, 1979).  Genes in different species with enough sequence similarity to be evolutionarily related (Hartwell, 2004).

Homozygous- Two copies of a gene that are identical (McEachern, 1991). Having identical alleles for the trait in question (Bechtel, 1995).

Hybrid- Any crossbred animal; heterozygous (Holmes, 1979).  Individuals resulting from a cross between parents of different genotypes (Allaby, 1985) Offspring of parents that differ in one or more heritable characters.  Also refers to offspring of parents of different species (Bechtel, 1995).To date, ball pythons have been crossbred with the Borneo python (Python breitensteini), the short-tailed python (Python curtus), the Angolan python (Python ancheitae), and the woma (Aspidites ramsayi).

Hypermorphic mutation- Produces an allele generating either more protein than the wild-type allele or the same amount of a more efficient protein.  If excess protein activity alters phenotype, the hypermorphic allele is dominant (Hartwell, 2004).

Hypomelanistic- A single recessive mutation that greatly reduces the amount of melanin but does not eliminate it entirely; the pupil of the eyes remains black, and the appearance of the organism is between that of normal and amelanistic (McEachern, 1991).  Containing decreased amount of black and brown melanin (Bechtel, 1995).  A descriptive term implying that the appearance of an organism contains less melanin than is typical in the wild condition; hypomelanistic snakes have a normal pattern, but the overall appearance is lighter because of a reduction in the dark pigments (Barker, 2006).

Hypomorphic mutation- Produces either less of a protein or a protein with a weak but detectable function (Hartwell, 2004).

Hypopigmented- Containing decreased amount of pigment (Bechtel, 1995).

Imbricate- Overlapping, as shingles on a roof (Barker, 2006).

Inbreeding (Line breeding)- Mating between closely related organisms (Klug, 2003).

Incomplete dominance- Expression of heterozygous phenotype that is distinct from, and often intermediate to, that of either parent (Klug, 2003).  Expression of heterozygous phenotype resulting in offspring whose phenotype is intermediate between those of the parents (Hartwell, 2004).

Infralabial- A scale in the series of labial scales bordering the lower lip, excluding the mental.  The infralabials are numbered from the anteriormost (which contacts the mental), posteriorward to the final posterior infralabial at the rictus (Barker, 2006).

Internasals- A pair of plate-like scales located on the anterior end of the snout between the nasals, usually in full medial contact (Barker, 2006).

Iridocytes- See iridophores.

Iridophores- Cells that lie between the melanophores and the xanthophores and contain pteridine platelets that reflect light (Bentley, 1982).  Guanine bodies, granules, or plates of which the reflective tissue of reptiles (and fishes) is composed (Holmes, 1979).  Iridescent chromatophores that produce color by physical rather than metabolic methods (Bechtel, 1995).

Labial pits- Infrared-sensitive depressions on the anterior supralabial scales and posterior infralabial scales (Barker, 2006).

Lateral- An anatomical direction away from the midline; pertaining to the sides.  Usually the terms lateral and medial are opposite directions (Barker, 2006).

Leucism- Paleness, as of coloration (Lincoln, 1990).  The condition of a totally or predominantly white appearance (Barker, 2006).

Leucistic- All pigment except that of xanthophores if absent, producing an all-yellow appearance (Mattison, 1986).  White, colorless, albinistic (Peters, 1964).  Appearing as white (Barker, 2006).  Absence of pigment (melanophores and xanthophores) through out the body with the exception if the animals iris; usually a solid white animal with black or blue eyes.

Leucophore- A white chromatophore (Holmes, 1979).  One of two types of guanophores characterized by the presence of guanine in the form of granules (Peters, 1964).  In general, leucophores and iridophores are both considered guanophores, but these two chromatophores should be distinguished because leucophores contain white granules laden with uric acid, whereas iridophores contain reflective platelets (Hama, 1975).

Linkage- Condition in which two or more nonallelic genes tend to be inherited together.  Linked genes have their loci along the same chromosome and do not assort independently, but can be separated by crossing over (Klug, 2003). The proximity of two or more markers on a chromosome; the closer together the markers are, the lower the probability that they will be separated by recombination.  Genes are linked when the frequency of parental type progeny exceeds that of recombinant progeny (Hartwell, 2004).

Lipochrome- An indefinite group of animal and plant pigments such as carotins, luteins, and zooerythrin (Holmes, 1979).

Lipophore- A wandering cell containing lipochrome (Holmes, 1979).  A chromatophore characterized by the presence of lipids in the form of oil droplets within which naturally occurring pigments are dissolved (Peters, 1964).

Locus- Position of a gene on a chromosome (Bechtel, 1995).

Loci- Plural of locus.

Longitudinal- Running lengthwise, parallel to the long axis of a python (Barker, 2006).

Loreal- An area on the side of the snout between the eye and the nose.  In ball pythons, loreals are scales in the loreal area, an area bounded by the supralabials, nasals, preoculars, and prefrontals (Barker, 2006).

Lutein- A yellow lipochrome, being a xanthophylls carotenoid (Holmes, 1979).

Mapping- The process of determining the locus of a gene on a particular chromosome (Hartwell, 2004).  The study of the position of genes on chromosomes.

Marker- An identifiable physical location on a chromosome, whose inheritance can be monitored.  Markers can be expressed regions of DNA (genes) or any segment of DNA that has variant forms which can be followed (Hartwell, 2004).  Any genetic element (locus, allele, DNA sequence or chromosome feature) which can be readily detected by phenotype, cytological or molecular techniques, and used to follow a chromosome or chromosomal segment during genetic analysis.

Medial- An anatomical direction meaning “in the middle” or “toward the midline.”  Usually the terms medial and lateral are opposite directions (Barker, 2006).

Melanin- One of a group of dark pigments found in the skin and formed in the melanoblast cells (melanophores) (Allaby, 1991).  A black or brown pigment (Bentley, 1982).  An amorphous, noncrystalline black compound manufactured in the melanosomes (Barker, 2006).  Black or brown pigments synthesized from tyrosine (Bechtel, 1995).

Melanism- Excessive amounts of black pigment (Holmes, 1979).  An unusual increase in the normal amount of black pigment within a particular individual as contrasted with other members of its species (Peters, 1964).  Occasionally used to characterize a species in which all individuals are equally black (Peters, 1964).  Abundance of black pigment, sometimes resulting in an all-black animal; the opposite of albinism (Conant, 1975).  A condition in which an animal has an unusually large amount of dark pigment so that it appears black or blackish (Arnold and Burton, 1978).  Not the same as anerythristic, which is the absence of red and orange pigment (McEachern, 1991).  Unusual darkening of normal pigmentation due to increased melanin (Bechtel, 1995).

Melanistic- The condition is which black pigments are accentuated, sometimes to the extent of obscuring all other color (Stebbins, 1966).  Totally black owing to the abundance of the black pigment, melanin, which obscures all other colors and markings (Mattison, 1986).  A term sometimes used erroneously for Anerythristic specimens (McEachern, 1991).

Melanophore- A cell found in the deep layers of skin that contains melanin (Bentley, 1982).  A chromatophore of a cold-blooded animal that synthesizes black or brown pigments known as melanin; melanophores are divided into dermal and epidermal, based on their location in the skin (Bechtel, 1995).

Melanosome- The organelle in a melanophore in which the synthesis if melanin and BCM occurs and in which these pigments are contained (Barker, 2006).

Melanotic- Having black pigment unusually developed (Holmes, 1979).  Dark colored as a result of an exceptional development in the amount of black pigment (McCoy, 1980).

Mental- The single large triangular scale on the front of the lower jaw (Barker, 2006).

Mental groove- The longitudinal groove or inward fold of skin on the chin (Barker, 2006).

Monohybrid cross- Breeding experiment in which parents differ in only one genetically determined trait (Bechtel, 1995).

Morph- One of the members of a polymorphic population (Holmes, 1979).  Visible form and structure of an organism (Bechtel, 1995).  Synonymous with appearance, or an individual or lineage with a particular appearance (Barker, 2006).

Morphologic- Pertaining to form and structure of an organism (Bechtel, 1995).

Multimeric protein- A protein made from more than one poleypeptide; each poleypeptide in the multimeric protein is called a subunit (Hartwell, 2004).

Multiple alleles- Three or more alleles of the same gene (Klug, 2003).  In a given population, more than twoalternative forms of a gene affecting a single inherited trait. The existence of several known alleles of a gene.

Mutagen- Any substance capable of altering genetic information (Bechtel, 1995).

Mutation- An abrupt change in the base sequence of DNA, resulting in new genetic information.  If the mutation is in a gamete, the new genetic information can be passed to the next generation (Bechtel, 1995).  The process producing a gene or a chromosome differing from the wild type.

Nasal- The scale surrounding the nostril (Barker, 2006).

Natural selection- Differential reproduction and survival of organisms do to environmental forces, resulting inpreservation of traits most fitted for survival (Bechtel, 1995).

Neomorphic mutation- Rare mutations that produce a novel phenotype due to production of protein with a new function or due to ectopic expression of the protein (Hartwell, 2004).

Nigrescent- Nearly black; blackish, turning black (Holmes, 1979).

Nigrismus- A type of Melanism in which the specimen is not completely black but shows a change in the elements of the basic pattern of its species as a consequence of the increased size of the black portion of its pattern (Peters, 1964).

Nonallelic genes- Not coded for the same trait; not paired (Bechtel, 1995).

Normal- An adjective used to refer to the expected or average condition of a character, trait, or appearance (Barker, 2006). See wild type.

Null Allele (Null mutation)- A nonexpressed allele; a mutation that completely eliminates function of a gene (Klug, 2003).  Mutation that abolish the function of a protein encoded by the wild type allele. Such mutations either prevent synthesis of the protein or promote synthesis of the protein incapable of carrying out any function (Hartwell, 2004).

Ocular- Pertaining to the eye.

Ontogenetic- Development of an individual organism. Changes occurring during postembryonic life are ontogenetic (Bechtel, 1995).

Organelle- A structure inside of a cell.  Organelles include mitochondria, ribosomes, Golgi bodies, and chromatosomes (Barker, 2006).

Oviparous- Reproducing by laying eggs (Bechtel, 1995).

Paedomorphosis (Neoteny)- Retention of juvenile characteristics by sexually mature individuals (Bechtel, 1995).

Paraventrals- The longitudinal series of scales adjacent to and contacting the lateral margin of the ventral scales.  The paraventral scales are the first row of dorsal body scales (Barker, 2006).

Parietals- The scales that cover the parietal area of the head, bounded by the frontal scales and supraoculars, uppermost postocular, temporals, and occipitals (Barker, 2006).

Phaeomelanin- Also pheomelanin.  A form of melanin that is light-brown or yellow (Mattison, 1986).  A brownish melanin (Holmes, 1979).  Red or yellow melanin (Bechtel, 1995).  A red-brown pigment produced by melanosomes,the end result of a reaction occurring in a melanosome, beginning with the precursor compounds of cysteine and dopaquinone (Nicolaus, 2001).

Phenotype- The observable manifestation of a specific genotype; the properties of an organism produced by the genotype in conjunction with the environment; organisms with the same overall genotype may have differences in phenotype because of the effects of gene and environmental interaction (Allaby, 1985).  Genetic constitution of a group of individuals (Holmes, 1979).  An organism described by its external appearance (Bechtel, 1995).  The phenotype of an organism or a group of similar organisms is the observable appearance (Barker, 2006).

Physiology- Science dealing with function of organisms and their parts (Bechtel, 1995).

Piebald- Spotted or patched, usually in black and white (Bechtel, 1995).

Poikilothermic (Ectothermic or cold-blooded)- Having no internal means for controlling body temperature (Bechtel, 1995).

Polychromatic- Having several colors as pigmented areas; two forms of erythrocytes with well-defined chromatin (Holmes, 1979).  Referring to a pattern or appearance composed of two or more colors (Barker, 2006).

Polymorphism- The appearance of more than one color type or pattern type within a single species or subspecies, not to be confused with occasional mutants such as albinos, nor with instances in which juveniles are marked differently from adults (Mattison, 1991).  The occurrence of two or more forms that are genetically distinct from one another but contained within the snake interbreeding population (Allaby, 1985).  The occurrence of more than one type of individual in a species (Branch, 1988).  Occurrence together of two or more distinct morphological forms of a species (Bechtel, 1995).

Posterior- An anatomical direction meaning toward the tail (Barker, 2006).

Posterior prefrontals- A group of 10 to 24 small scales bounded in the front by anterior prefrontals, in the back by frontals and supraoculars, and on the sides by loreals and the upper preoculars (Barker, 2006).

Proteins- Large polymers composed of hundreds to thousands of amino-acid subunits strung together in a specific order into long chains. Proteins are required for the structure, function, and regulation of the body’s cells, tissues, and organs (Hartwell, 2004).

Prefrontals- The scales on top of the snout in the area bounded by the frontal scales, supraoculars, upper preoculars, the loreal scales, and the internasals.  In ball pythons, the prefrontals are divided into two types: anteriorprefrontals and posterior prefrontals (Barker, 2006).

Preoculars- Scales in contact with the anterior margin of the eye (Barker, 2006).

Preventral- An anterior scale or scales in the ventral scale series, distinguished from a ventral by being bounded on one or both lateral margins by gular scales, whereas ventrals are laterally bounded by the paraventral series of scales (Barker, 2006).

Progeny- The offspring produced from a mating (Klug, 2003).  The subsequent generation following a mating or crossing of parents; offspring.

Pteridine- A class of chemicals incorporated in xanthophore pigments (Bechtel, 1995).

Pteridine platelets- Organelles in a chromatophore that reflect light and produce an iridescent appearance (Bentley, 1982).

Punnett square- Named after the British mathematician Reginald Punnett, who introduced it in 1906. The square provides a simple and convenient method for tracking the kinds of gametes produced as well as all the possible combinations that might occur at fertilization (Hartwell, 2004).

Recessive gene- A character or gene possessed by one parent that in a hybrid [heterozygous condition] is masked by the corresponding alternative or dominant character derived from the other parent (Holmes, 1979).  A gene whose effect is expressed in the homozygous state, but masked in the presence of a dominant allele when the organism is heterozygous for that gene (Allaby, 1985).  A gene that can determine the phenotype only in the homozygous state (Bechtel, 1995).

Recombination- The process that leads to the formation of new gene combinations on chromosomes (Klug, 2003).  The process by which offspring derive a combination of genes different from that of either parent; the generation of new allelic combinations. In higher organisms, this can occur by crossing over (Hartwell, 2004)

Rictus- The corner of the mouth; the juncture of the upper and lower lips (Barker, 2006).

Rostral- The single large scale on the front of the upper jaw.  In pythons, this scale is bordered by the anteriormost supralabials, nasals, and internasals (Barker, 2006).

Rufinism- Red pigmentation caused by inhibition of the formation of dark pigment (Holmes, 1979).

Rutilism- Same as rufinism.

Schemochrome- A color created by the structure of a chromatophore and not resulting from an actual pigment (Nicolaus, 2001).  Many of the colors created by iridophores are schemochromes (Barker, 2006).

Sex chromosome- Special sex-determining chromosome (Bechtel, 1995).

Sex-linked- Genetic traits that determined by genes carried on a sex chromosome (Bechtel, 1995).

Sexual dimorphism- Gender differences in characteristics (Bechtel, 1995).

Siblings- Two or more offspring of the same parents (Bechtel, 1995).

Species- Group of organisms which interbreed and are reproductively isolated from all other such groups (Bechtel, 1995).

Subcaudal- Referring to the region of the underside of the tail (Barker, 2006).

Subcaudals- In ball pythons, a series of paired scales on the underside of the tail from immediately behind the vent to, but not including, the terminal scale on the tip of the tail.  The first row of subcaudals constitutes the posterior margin of the cloacal opening; this row may be composed of irregularly shaped small scales, unlike the subsequent uniform paired scales of the series.  The first subcaudal row may be partly covered by the anal scale.  The first row is counted when recording the number of subcaudals (Barker, 2006).

Subocular- A scale in contact with the lower margin of the eye that is not in contact with the margin of the upper lip.  Some ball pythons have a scale in the circumocular series that is clearly definable as a subocular, whereas others have only supralabial scales in contact with the lower margin of the eye (Barker, 2006).

Subspecies- Well-defined geographic or physiologic aggregate of local population which differs from other such subdivisions of the same species (Bechtel, 1995).

Supralabials- The series of labial scales bordering the lips of the upper jaw, excluding the rostral.  The supralabials are numbered from the anteriormost (which contacts the rostral) posteriorward to the final posterior supralabial at the rictus (Barker, 2006).

Supraocular- A scale above the eye, in contact with the upper margin of the eye (Barker, 2006).

SVL- Abbreviation for snout-vent length, a measure of length from the tip of the nose to the posterior margin of the anal scale (Barker, 2006).

Taxa- Plural of taxon (Barker, 2006).

Taxon- A grouping of organisms given a proper name; for example, a subspecies is a taxon.  A species is also a taxon, but of a different level of classification from a subspecies (Barker, 2006).

Taxonomy- Scientific naming of organisms and their classification with reference to their precise position in the plant or animal kingdom (Bechtel, 1995).

Temporals- Small scales on the side of the head in the area bounded by the postoculars, posterior supralabials, and the parietals, extending posteriorward to the area above the angle of the jaw (Barker, 2006).

Terrestrial- Living on ground (Bechtel, 1995).

Trait- Any detectable phenotypic variation of a particular inherited character (Klug, 2003).

Transverse- Crosswise; passing or lying across the body; an anatomical direction perpendicular to the long axis of a python (Barker, 2006).

Tyrosinase- The enzyme essential in synthesis of melanin (Bechtel, 1995).  An enzyme.  According to Raper-Mason Melanogenesis, tyrosinase is an enzyme necessary to the synthesis of tyrosine into dopa, and then of dopa into dopaquinone; the precursor compound for eumelanin and Phaeomelanin (Barker, 2006).

Tyrosinase-negative albinism- Albinism due to absence of tyrosinase (Bechtel, 1995).

Tyrosinase-positive albinism- Albinism in animals capable of synthesizing tyrosinase, but yet unable to synthesize melanin (Bechtel, 1995).

Tyrosine- The amino acid precursor of melanin, thyroxine, and adrenalin (Bechtel, 1995).

Unilateral- Found only on one side (Bechtel, 1995).

Variant- Differing from normal (Bechtel, 1995).

Vent- The cloacal opening; also termed the anus (Barker, 2006).

Ventral- Pertaining to the under or lower surface (venter) (Bechtel, 1995).

Ventrals- The ventral scales; the longitudinal series of wide scales covering the belly of a python from the neck posteriorward to the anal scale.  Counts of the ventral scales do not include the anal scale.  Ventrals are always bordered by the paraventral series of scales.  The anteriormost ventral is distinguished from preventrals by being bounded on both lateral margins by the paraventrals (Barker, 2006).

Ventrolateral- Pertaining to the area between the ventral surface and lateral surfaces (Barker, 2006).

Wild type- The phenotype occurring normally or with the greatest frequency in the wild population (Bechtel, 1995).  The “normal” appearance of a species (Barker, 2006).

Xanthic- Having only red pigment in the skin (Branch, 1988).  In common usuage, an appearance dominated by an apparent surplus of yellow color (Barker, 2006).  Abundance of xanthophores (yellow pigment) (Bechtel, 1995).

Xanthine- Red pigment (Bentley, 1982).  Derived from the Greek word xanthos, meaning “yellow,” most xanthine pigments are yellow in color.  It is a purine compound, being an intermediate in the degradation of adenosine monophosphate to uric acid (Barker, 2006).

Xanthophore- Pigment cell synthesizing red, yellow, and intermediate pteridine pigments (Bechtel, 1995).  A chromatophore with pteridine pigments synthesized and contained in pterinosomes, and carotenoid pigments in oil-filled vesicles.  For example, dermal xanthophores are believed to be responsible for the yellow pattern seen on albino ball pythons (Barker, 2006)

Bibliography

Bechtel, H. B. 1995. Reptile and Amphibian Variants: Colors, Patterns, and Scales. Krieger Publishing Company, Malabar FL.

Klug, W. and M. Cummings. 2003. Concepts of Genetics Seventh Edition. Pearson Education, Inc.

Hartwell, L., L. Hood, M. Goldberg, A. Reynolds, L. Silver and R. Veres. 2004. Genetics From Genes to Genomes Second Edition. McGraw-Hill.

Barker D., and T. Barker. 2006. Pythons of the World, Volume II Ball Pythons: The History, Natural History, Care and Breeding. VPI Library.