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What is the difference between genetic maternal effect and genomic imprinting?

If there are five alleles at a locus, how many genotypes can there be at this locus? How many different kinds of homozygotes can there be? How many genotypes and homozygotes can there be with eight alleles at a locus?

Mu 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 \(\left(B_{-} R_{-}\right)\) are brown, fish with a dominant allele at the \(B\) locus only \(\left(B_{-} r r\right)\) are blue, fish with a dominant allele at the \(R\) locus only \(\left(b b R_{-}\right)\) are red, and fish with recessive alleles at both loci \((b b r r)\) are white. Aida crossed a homozygous brown fish with a homozygous white fish. He then backcrossed the \(\mathrm{F}_{1}\) with the homozygous white parent and obtained 228 brown fish, 230 blue fish, 237 red fish, and 222 white fish. a. Give the genotypes of the backcross progeny. b. 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? c. What results would you expect for a cross between a homozygous red fish and a white fish? d. What results would you expect if you crossed a homozygous red fish with a homozygous blue fish and then backcrossed the \(\mathrm{F}_{1}\) with a homozygous red parental fish?

Male-limited precocious puberty results from a rare, sex-limited autosomal allele \((P)\) that is dominant over the allele for normal puberty \((p)\) and is expressed only in males. Bill underwent precocious puberty, but his brother Jack and his sister Beth underwent puberty at the usual time, between the ages of 10 and \(14 .\) Although Bill's mother and father underwent normal puberty, two of his maternal uncles (his mother's brothers) underwent precocious puberty. All of Bill's grandparents underwent normal puberty. Give the most likely genotypes for all the relatives mentioned in this family.