Inheritance Terminology

homologue

pair of homologous MA and PA chromosomes

autosomes

chromosomes of homologues 1-22

homologue

pair of homologous MA and PA chromosomes

autosomes

chromosomes of homologues 1-22

sex chromosomes

X and Y chromosomes; Y determines sex

gene locus

location of a gene on a chromosome

allele

a specific version of a gene found on a MA or PA chromosome; in diploid (2n) biota alleles control the expression of a gene locus as a trait

dominant allele

an allele that is typically always expressed (expressed by ‘R’)

recessive allele

an allele expressed only the absence of a dominant allele (expressed by ‘r’)

genotype

the two alleles inherited for a particular gene locus (e.g. RR)

trait

the outward expression of a gene locus (e.g. Rh blood type)

character states

the versions of a trait (e.g. Rh+ or Rh- blood type)

phenotype

the character state expressed for a given genotype (e.g. Rh+ blood type)hom

homozygote

individual who inherited 2 identical alleles for a gene locus (e.g. RR)

heterozygote

individual who inherited different alleles for a gene locus (e.g. Rr)

homozygous dominant

homozygote with dominant alleles at gene locus (RR)

homozygous recessive

homozygote with recessive alleles at gene locus (rr)

co-dominant heterozygote

heterozygote with 2 different dominant alleles (e.g. I^A I^B)

mutation

process that generates new alleles in a population

polyallelic gene locus

gene locus with 3+ alleles in the population

gene pool

all alleles for a gene locus in a population

expression

process of when a gene locus is transcribed/translated into a protein that manifests as a trait

expression relationship

a model describing how different alleles of a gene locus are expressed in the same individual