Ch. 9 Complex Inheritance

Complex Inheritance Complex inheritance shows a variation of inheriting traits with the differences in the heterozygous individuals 4 types: Incomplete dominance Codominance Multiple alleles Sex-linked dominance

Incomplete Dominance Heterozygous individual shows a blending of traits Snapdragons show incomplete dominance with the blending of the red flower color and the white flower color to produce a pink flower color. In snapdragons, the heterozygous individual shows incomplete inheritance. Two pink snapdragons are crossed. Explain the percentages of the different possible phenotypes.

Codominance Heterozygous individual shows both traits. Roan cows are an example of codominance of the red and white coat color. Cows exhibit codominance with roan cows having both red and white coats. A red and white cow mate. Explain the percentages of the possible phenotypes.

Multiple Alleles Inheritance that shows complete dominance in some alleles and incomplete or codominance in other alleles. ABO blood type is an example of multiple alleles. Blood types A and B are co-dominant to each other but completely dominant to blood type O. A woman with blood type O has a child with type O blood. The woman’s husband is blood type A (unknown genotype) and believes the child is not his. Is her husband correct? Why or why not?

Sex-linked Dominance Traits or diseases that are associated with the sex chromosomes. Typically, these traits are linked to the X-chromosome. Male patterned baldness, hemophilia, and color blindness are X- linked recessive genes.

X-linked Recessive Problem Male patterned baldness is a sex-linked recessive trait. A woman who is a carrier for the trait has a son with a man who does not have the trait. What is the probability that their son will have male patterned baldness? If they had a daughter, what would be the probability for her to have the trait?