Download mendelian genetics vocabulary

MENDELIAN GENETICS VOCABULARY
1.
(2013)
Allele: is an alternate form of a gene for one trait. For example, brown and blue eyes are two different alleles for eye
color.
2. Autosome: a chromosome that is not a sex chromosome.
3. Breeding: the process of producing offsprings by sexual reproduction
4. Codominance: the phenomenon in which a single gene has more than one dominant allele. An individual who is heterozygous
for two codominant alleles will express both traits in its phenotype.
5. Cross: breeding of two individuals with different genotype/phenotype
6. Cross-test: method used to determine if a group exhibiting a dominant trait is homozygous or heterozygous for that
trait. More simply put, test crosses determine the genotype of an individual with a dominant phenotype.
7. Diploid: a cell or organism, with two sets of chromosomes (2n).
8. Dominant: observed trait of an organism that mask the recessive allele of a trait.
9. Epistasis: is a phenomenon in which the expression of one gene depends on the presence of one or more other genes called
"modifier genes."
10. Filial generation (F): the offspring generation originated from the mating of the parental generation. F1 is the first filial
generation; F2 is the second; and so on.
11. Gamete: The male and female sex cells that come together during the reproduction process
12. Genes: are the smallest chemical parts that form segments of chromosomes. Genes determine what we look like.
13. Genotype: is the actual code that alleles or genes possess (E.g. Tt or TT or tt). The gene may or may not be expressed
when you observe a living organism.
14. Haploid: a cell or organism with just one set of chromosomes (n).
15. Heterozygous: a genotype consisting of two different alleles of a gene for a particular trait. An individual that is
heterozygous (Aa) is also referred to as hybrids.
16. Homozygous: a genotype consisting of two identical alleles of a gene for a particular trait. An individual may be
homozygous dominant (AA) or homozygous recessive (aa). Individuals who are homozygous for a trait are also referred to
as homozygotes.
17. Hybrid: any offspring resulting from the mating of two genetically distinct individuals. It is synonymous with
heterozygous. If the parents differ for just one trait, the hybrid is called monohybrid, if they differ for two traits it is
called dihybrid, and so on.
18. Incomplete dominance: a heterozygous condition in which both alleles at a gene locus are partially expressed, often
producing an intermediate phenotype.
19. Interbreeding: reproduction between genetically different individuals.
20. Locus (pl.loci): the specific location of a gene on a chromosome.
21. Parental generation: the first set of parents crossed to produce a filial generation.
22. Pedigree: a “family tree”. A chart of an individual's ancestors used in human genetics to analyze Mendelian inheritance of
certain traits, especially of familial diseases.
23. Phenotype: the observable or detectable characteristics of an individual organism--the observable expression of a
genotype.
24. Pleiotropy: when one gene influences multiple phenotypic traits.
25. Polymorphic gene: condition in wich a gene is represented by more than one allele.
26. Probability: the likelihood that a specific event will occur. Probability is usually expressed as the ratio of the number of
actual occurrences to the number of possible occurrences.
27. Punnett Square: a simple graphical method of showing all of the potential combinations of offspring genotypes that can
occur and their probability given the parent genotypes.
28. Recessive: trait of an organism that can be masked by the dominant form of a trait
29. Sex chromosome: a type of chromosome that is involved in the determination of the sex as well as the development of
sexual characteristics in an organism (X and Y in the human genome).
30. Trait: a genetic characteristic of an organism
31. True-breeding: organisms that are identical genetically for many generations because they are homozygous.
32. Wild-type: the most common allele appearing in a population in the wild.