genetics - Biol 215 Genetics p 1 of 4 1 In squash a gene...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Biol 215 Genetics. p. 1 of 4 1. In squash a gene for white color ( W ) is dominant over its allele for yellow color ( w ). Give the gcnotypic and phcnotypic ratios for the results of each of the following crosses: W/W × w/w W/w × w/w W/w × W/w 2. If pollen from the anthers of a heterozygous white-fruited squash plant is placed on the pistil of a yellow-fruited plant, show, using ratios, the genotypes and phenotypes you would expect the seeds from this cross to produce. 3 In human beings, cystic fibrosis is an autosomal recessive trait ( c ). Give the genotypic and phenotypic ratios for the following crosses: homozygous normal × heterozygous heterozygous × CF individual 4. This is a pedigree for a rare heart condition that causes the heart to stop beating when a person is in their 20s. What is the most likely mode of inheritance of this disease? 5 If the litter resulting from the mating of two short-tailed cats contains three kittens without tails, two with long tails, and six with short tails, what would be the simplest way of explaining the inheritance of tail length in these cats? Show genotypes. 6. Schilder’s disease is a progressive degeneration of the central nervous system that leads to death at age 2 years. The disease is caused by a simple autosomal recessive mutation. A couple loses its first two children to Schilder’s disease. If they decide to have a third child, what is the probability that it will have the disease? 7. In peas a gene for tall plants (T) is dominant over its allele for short plants (t). The gene for smooth peas (S) is dominant over its allele for wrinkled peas (s). Calculate both phenotypic ratios and genotypic ratios for the results of each of the following crosses: T/t S/s × T/t S/s T/t s/s × t/t s/s t/t S/s × T/t s/s T/T s/s × t/t S/S 8. In hogs a gene that produces a white belt around the animal's body is dominant over its allele for a uniformly colored body. Another independent gene produces fusion of the two hoofs on each foot (an instance of syndactyly); it is dominant over its allele, which produces normal hoofs. Suppose a uniformly colored hog homozygous for syndactyly is mated with a normal-footed hog homozygous for the belted character. What would be the phenotype of the F 1 ? If the F 1 individuals are allowed to breed freely among themselves, what genotypic and phenotypic ratios would you predict for the F 2 ? 9. In watermelons the genes for green color and for short shape are dominant over their alleles for striped color and for long shape. Suppose a plant with long striped fruit is crossed with a plant hctcrozygous for both these characters. What phenotypes would this cross produce and in what ratios?
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Biol 215 Genetics. p. 2 of 4 10. In the fruit fly Drosophila melanogaster, vestigial wings and hairy body arc produced by
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 4

genetics - Biol 215 Genetics p 1 of 4 1 In squash a gene...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online