Question

short answer. write the word or phrase that best completes each statement or answers the question on separate sheet of paper. 1) assume that you have a garden and some pea plants have solid leaves and others have striped leaves. you conduct a series of crosses (a through e) and obtain the results given in the table. cross progeny solid striped (a) solid x striped 55 60 (b) solid x solid 36 0 (c) striped x striped 0 65 (d) solid x solid 92 30 (e) solid x striped 44 0 define gene symbols and give the possible genotypes of the parents of each cross. 2) the phenotype of vestigial (short) wings (g) in drosophila melanogaster is caused by a mutant gene that independently assorts with a recessive gene for hairy (h) body. the wild - type (gghh x gghh) were crossed among each other to produce 1024 offspring. what phenotypes would you expect among the 1024 offspring, and how many of each phenotype would you expect? 3) a certain type of congenital deafness in humans is caused by a rare autosomal dominant gene. (a) in a mating involving a deaf man and a deaf woman (both heterozygous), would you expect all the children to be deaf? explain your answer.

Explanation:

Step1: Analyze cross (a)

The ratio of solid - striped in cross (a) (55 solid and 60 striped) is approximately 1:1. Let the allele for solid leaves be \(S\) and for striped leaves be \(s\). A cross of \(Ss\times ss\) would give a 1:1 ratio of solid (\(Ss\)) to striped (\(ss\)) offspring. So the parents are \(Ss\) (solid) and \(ss\) (striped).

Step2: Analyze cross (b)

All offspring are solid in cross (b). This implies that both parents are homozygous. Since solid is the dominant trait (from cross - analysis), the parents are \(SS\times SS\) or \(SS\times Ss\). But if one of them was \(Ss\), we would expect some striped offspring in a large enough sample. So the most likely genotypes are \(SS\times SS\).

Step3: Analyze cross (c)

All offspring are striped in cross (c). Since striped is the recessive trait, the parents must be \(ss\times ss\).

Step4: Analyze cross (d)

The ratio of solid to striped in cross (d) (92 solid and 30 striped) is approximately 3:1. This is the classic Mendelian ratio for a cross between two heterozygotes. So the parents are \(Ss\times Ss\).

Step5: Analyze cross (e)

All offspring are solid in cross (e). Since one parent is striped (\(ss\)), the solid - leafed parent must be \(SS\) to ensure all offspring are \(Ss\) (solid). So the parents are \(SS\times ss\).

For cross (a): Parent 1 (solid) is \(Ss\), Parent 2 (striped) is \(ss\).
For cross (b): Parent 1 (solid) is \(SS\), Parent 2 (solid) is \(SS\).
For cross (c): Parent 1 (striped) is \(ss\), Parent 2 (striped) is \(ss\).
For cross (d): Parent 1 (solid) is \(Ss\), Parent 2 (solid) is \(Ss\).
For cross (e): Parent 1 (solid) is \(SS\), Parent 2 (striped) is \(ss\).

Answer:

Cross (a): Parent 1: \(Ss\), Parent 2: \(ss\)
Cross (b): Parent 1: \(SS\), Parent 2: \(SS\)
Cross (c): Parent 1: \(ss\), Parent 2: \(ss\)
Cross (d): Parent 1: \(Ss\), Parent 2: \(Ss\)
Cross (e): Parent 1: \(SS\), Parent 2: \(ss\)