Extension of Mendelian Genetics Flashcards
Incomplete Dominance
a form of intermediate inheritance in which one allele for a specific trait is not completely expressed over its paired allele. Results in a third phenotype in which the expressed physical trait is a combination of the phenotype’s of both alleles.
Codominance
a form of dominance wherein the alleles of a gene pair in heterozygote are fully expressed. This results in offspring with a phenotype that is neither dominant or recessive.
Complete Dominance
Phenotype of the heterozygote is the same as the phenotype of one of the homozygotes
Penetrance
the percentage of individuals having a particular genotype that express the expected phenotype
Expressivity
the degree to which a trait is expressed
Lethal alleles
allele that causes death at an early stage of development, affecting the Mendelian genotype and phenotype ratios in progeny
Multiple alleles
For a given locus, more than two alleles are present within a group of individuals
Epistasis
a interaction among genes, a phenomenon where the effect of one gene is dependent on the presence of genetic background.
Epistatic gene
when a gene or locus suppresses or masks the phenotypic expression of another gene
Hypostatic gene
the gene or locus which was suppressed by an epistatic gene
Recessive Epistasis
the presences of two recessive alleles inhibits the expression of an allele at a different locus
Dominant Epistasis
only a single copy (heterozygous) of an allele is required to inhibit expression of an allele at a different locus
Bombay Phenotype
Expression of the ABO antigens depends on alleles at the H locus. The H locus encodes a precursor to the antigens called compound H
Duplicate Epistasis
Recessive, two recessive alleles at either of two different loci are capable of suppressing a phenotype. Dominant, a single dominant allele at either of two loci is capable of suppressing a phenotype
Sex-Influenced
determined by autosomal genes and are inherited according to Mendel’s principles, but are expressed differently in males and females. A particular trait has a higher penetration in one of the sexes.
