Extensions to Mendelian Ratios
1.
In cattle, the alleles for red coat and white coat are codominants. Both red and white hare are produced so that the heterozygote is intermediate or roan colored. a.
Assign proper letters for each allele. b.
Give the phenotypic and genotyped ratios to be expected among the offspring from a cross of 2 roan animals c.
What are the expected genotypic and phenotypic ratios from a cross of a roan animal and a white one?
2.
In certain breeds or chickens, the factor (B 1 ) is responsible for production of black feathers and its allele (B 2 ) produces feathers that are basically white (except for flecks of black). The heterozygote is blue-feathered. Another factor (F 1 ) produces straight feathers, whereas its allele (F 2 ) results in a frizzled condition, giving brittle feathers.
The heterozygote is mildly frizzled. What is to be expected from the following crosses? Give phenotypic ratios. a.
A black, frizzled hen X a white, straight rooster b.
A white, frizzled hen X a blue, straight rooster c.
A blue, mildly frizzled hen X a white, frizzled rooster d.
A blue, mildly frizzled hen X a blue, mildly frizzled rooster
3.
In rabbits, a multiple allelic series affects the color of the fur. Dark fur (f + ) is dominant to all the other alleles in the series. The allele (f h ) for Himalayan is dominant to albino (f a ). However, the allele for chinchilla coat color (f c ) gives a light gray color when present with either the allele for Himalayan or albino. Give the genotypes and the phenotypes of the following crosses. a.
A Himalayan rabbit who had an albino parent X a chinchilla colored rabbit b.
An animal with dark fur which had a chinchilla parent X a rabbit that is albino c.
A light gray animal which had an albino parent X a light gray which had a Himalayan parent
4.
There are 2 subgroups of type A blood which can be recognized. The allele A 1 is dominant to A 2 and O. A 2 is also dominant to O. A and B are codominant. B is also dominant to O. Give the results of the following crosses. a.
An A 1 type person who had an O parent X an A 2 who an O parent b.
An A 2 type person who had an O parent X an A 1 B c.
A 1 B X A 2 B d.
A 1 B X O