In sweet-pea plants, the gene A/a controls flower colour. The dominant allele gives purple flowers and the recessive allele red flowers. A second gene, B/b, controls the shape of the pollen grains. The dominant allele gives elongated grains and the recessive allele spherical grains.

A plant with the genotype AaBb was test-crossed by interbreeding it with a plant with red flowers and spherical pollen grains.

Using a genetic diagram to solve the problem, write the expected genotypes and phenotypes as well as the expected ratio of the offspring from this cross.

To answer this question, researchers studied populations of the dusky salamander (desmognathus ochrophaeus) living on different mountain ranges in the southern appalachian mountains. the researchers tested the reproductive isolation of pairs of salamander populations by leaving one male and one female together and later checking the females for the presence of sperm. four mating combinations were tested for each pair of populations (a and b)—two within the same population (female a with male a and female b with male b) and two between populations (female a with male b and female b with male a). the proportion of successful matings for each mating combination was measured. for example, when all the matings of a particular combination were successful, the researchers gave it a value of 1; when none of the matings were successful, they gave it a value of 0. then the researchers calculated an index of reproductive isolation that ranged from 0 (no isolation) to 2 (full isolation). the reproductive isolation value for two populations is the sum of the proportion of successful matings of each type within populations (aa + bb) minus the sum of the proportion of successful matings of each type between populations (ab + ba). the table provides data for the geographic distances and reproductive isolation values for 27 pairs of dusky salamander populations.

Resperation is a way to release carbon back into the atmosphere

The punnett square predicts the ratio of genotypes in the offspring, based on the genotypes of the parents. in this cross, tallness (h) is dominant to shortness (h). based on the punnett square, what is the phenotype of the offspring? hh hh tall short