Question #12600176

Can someone please help with these 4 biology questions?

1) The allele N codes for a normal nose and the allele n codes for a green nose. If two individuals who are both heterozygous at this gene location mate with each other, what combinations of alleles will their offspring have (genotype ratio)? What will their noses look like (phenotypic ratio)? 2) In pea plants, the allele for tall plants (T) is dominant to the allele for short plants (t). You observe that the offspring of a cross include 78 tall plants and 27 short plants. 1) What was the probable allele combination of the two parent plants? 2) How would your answer change if the offspring included 11 tall plants and 118 short plants? 3) In certain cells, tail length is determined by a gene that demonstrates incomplete dominance. The allele that causes a long tail (T) is not completely dominant over the allele that causes no tail (t). If a cat is heterozygous for this trait (Tt), then the cat will have a short tail. What is the probability that the offspring will be manx cats. (no tails) if a short-tailed cat is bred with a manx cat (no tail)? 4) The type of headcomb possessed by a chicken is determined yb two different genes. R and P are dominant alleles of the two genes, r and p are the recessive alleles of the two genes. R_pp codes for a nose com rrP_codes for a pea comb R_P_ codes for a walnut comb rrp codes for a single comb (The "_" indicates that either allele may be present here. Do you understand why it doesn't matter which allele is present here.) Suppose a hen and rooster who both have allele combinations of RrPp mate. What will be the ratio of the 4 types of comb among the offspring (phenotype ratio)? Thanks in advance.

2013-12-19 04:15:11

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