Tatuo Aida investigated the genetic basis of color variation in the medaka (Aplocheilus latipes), a small fish found in Japan (T. Aida. 1921. Genetics 6:554–573). Aida found that genes at two loci (B, b and R, r) determine the color of the fish: fish with a dominant allele at both loci (B_ R_) are brown, fish with a dominant allele at the B locus only(B_ rr) are blue, fish with a dominant allele at the R locus only (bb R_) are red, and fish with recessive alleles at both loci (bb rr) are white. Aida crossed a homozygous brown fish with a homozygous white fish. He then backcrossed the F1 with the homozygous white parent and obtained 228 brown fish, 230 blue fish, 237 red fish, and 222 white fish.   Q. Use a chi-square test to compare the observed numbers of backcross progeny with the number expected. What conclusion can you make from your chi-square results?

In the yawncat (a rare hypothetical animal), the dominant allele R causes solid tail color, and the recessive allele r results in white spots on a colored background. The black coat color allele B is dominant to the brown allele b, but the B and b alleles can only be expressed if the animal has an mm genotype at a third gene locus. Animals that are M_ are yellow regardless of which allele from the B locus is present. A mating between a solid yellow-tailed male yawncat and a solid brown-tailed female yawncat produces 16 offspring with the following tail phenotypes: six solid yellow, two spotted yellow, three solid black, one spotted black, three solid brown, and one spotted brown. What is the probability of the next offspring from these same two parents having a spotted brown tail? O A. 1/16 B. 9/16 С. 3/16 D. 1/2 O E. 1/4

Pink eye and albinism are two recessive traits found in the deer mouse, Peromyscus maniculatus. In mice with pink eye, the eye is devoid of color and appears pink from the blood vessels within it. Albino mice are completely lacking color both in their fur and in their eyes. F. H. Clark crossed pink‑eyed mice with albino mice; the resulting F1 had normal coloration in their fur and eyes. He then crossed these F1 mice with mice that were pink‑eyed and albino and obtained the mice shown in the table below. It is very hard to distinguish between mice that are albino and mice that are both pink‑eyed and albino, so he combined these two phenotypic classes (F. H. Clark, 1936, Journal of Heredity 27:259−260). Match the expected numbers of progeny with each phenotype if the genes for pink‑eye and albinism assort independently. Phenotype Observed Expected wild type, wild type 12   wild type, pink eyes 62   albino, wild type, or pink eyes 78   Total 152 152     Answer…

In cats, white patches are caused by the dominant allele P while p/p individuals are solid colored. Short hair is caused by the dominant allele S, while s/s cats have long hair. A longhaired cat with patches whose mother was solid-colored and shorthaired mates with a shorthaired, solid-colored cat whose mother was longhaired and solid-colored. What kinds of kittens can arise from this mating and in what proportions? Outline the cross and assign genotypes, phenotypes, and proportions in the space below. P​long hair, white patches​x​short hair, solid colored ​s/s ; P/p​S/s ; p/p F1 progeny: 1/4 s/s ; P/p​long hair, white patches 1/4 s/s ; p/p​long hair, solid colored 1/4 S/s ; P/p​short hair, white patches 1/4 S/s ; p/p​short hair, solid colored