Multiple factor inheritance

When two or more nonallelic gene pairs affect the same character in the same way, it is called

• pleiotropy

• polygenic inheritance

• additive expressivity

• total penetrance

Traits which show continuous variation is referred as ___________.

• Genetic disorders

• Phenotypic variation

• Quantitative traits

• Qualitative traits

For a quantitative trait, if two individuals with extreme phenotypes are mated, the offspring ________________.

• will have a range of phenotypes, most will be intermediate

• will have a range of phenotypes, most will be at the extremes

• all offspring will have intermediate phenotypes

• all offspring will have extreme phenotypes

For a quantitative trait, if two individuals with intermediate phenotypes are mated, the offspring ________________.

• will have a range of phenotypes, most will be intermediate

• will have a range of phenotypes, most will be at the extremes

• all offspring will have intermediate phenotypes

• all offspring will have extreme phenotypes

If three genes controlled skin color and the following were mated (R₁r₁R₂r₂R₃r₃ X R₁r₁R₂r₂R₃r₃), what proportion of offspring would be white (i.e., no alleles for skin pigmentation)?

• 15/64

• 20/64

• 1/64

• 6/64