BIO 111 Lecture 21: BIO 111 11/28/16
Document Summary
A few are on the sex chromosomes ( x or y ) X chromosome is larger; has more genes. Some alleles on x-linked genes are recessive and cause disorders or an altered phenotype. Recessive: only see phenotype/symptoms when no dominant allele is present. X-linked disorders are more common in males than females! One good allele can mask the disease allele. ~ 8% of the male population has some degree of colorblindness. ~ 0. 5% of the female population has some degree of colorblindness. (1910) thomas hunt morgan studied an x-linked trait (white vs red eyes) in fruit flies. For some species, the environment (not genes) determines the sex of offspring. Ex. , temperature of eggs in the nest matters. 33" c = baby alligators are male. In some fish, sex is controlled dominance hierarchy. A dominant male will turn female when the current female of the group dies. Plants: for most species, all individuals are both male and female.
