Biology: Chapter 5A, 5.5 Review Questions

Compare incomplete dominance with codominance, using examples at support.

Incomplete dominance is a heterozygous genotype that creates an intermediate phenotype. An example is the color of flowers. Codominance, neither phenotype is recessive. The heterozygous individual expresses both phenotypes. An example of this is the AB and O blood types.

Describe the concept of independent assortment.

It is the segregation of one set of alleles during gamete formation. It is not affected by the presence or segregation of other sets of alleles.

Describe the condition of multiple alleles. What human characteristic is controlled by multiple alleles?

Multiple alleles occur when one or more than two alleles can occupy a given locus. Blood type in humans is controlled by this because AB and O are all at the same locus even though each individual will juts have one.

Describe polygenic inheritance and distinguish between it and multiple alleles.

Multiple gene interaction occurs when two or more genes are needed to produce a single trait. Multiple alleles is when several alleles may be at a given locus. The phenotype depends on which allele is at the locus.

Compare simple dominance with incomplete dominance. List several examples of incomplete dominance.

Simple dominance is when the dominant gene in a heterozygous organism expresses the dominant phenotype. Incomplete dominance is when a heterozygous organism exhibits a blending of both genes, recessive and dominant. Red and white flowers will "blend" and make pink flowers. Another example is brachydatyly; when heterozygous individuals have some short fingers and homozygous individuals for the abnormal gene are severely crippled with a lack of fingers.