In a cross between two true-breeding individuals, a black and a white guinea pig, the F2 generation is of approximately 3/4 black and 1/4 white guinea pigs. What is the phenotype of the offspring made up in the F1 generation?

In a series of crosses involving pea plants that have round or wrinkled seeds (round is dominant to wrinkled) and yellow or green seeds (yellow is dominant to green), the following ratios were observed in the progeny: Parents -----> Progeny a) round, green x wrinkled, yellow -> 100% round, yellow b) round, yellow x round, yellow ---> 9/16 round, yellow 3/16 round, green 3/16 wrinkled, yellow 1/16 wrinkled, green c) round, yellow x round, yellow ----> 3/4 round, yellow 1/4 wrinkled, yellow d) wrinkled, yellow x round, yellow -----> 6/16 wrinkled, yellow 2/16 wrinkled, green 6/16 round, yellow 2/16 round, green On the basis of these progeny ratios, determine a possible genotype for each of the parent plants in each set of crosses (a,b, c, and d). Sometimes more than one genotype is possible, but you need only suggest one.

Dr. Thompson learned in her university genetics course to memorize probability outcomes from monohybrid crossing scenarios so there is never a need for drawing Punnett squares or forked line diagrams. Which equation would Dr. Thompson use to predict the probability of obtaining a tester outcome from the cross of MmNn X Mmnn?     a) ¼ mm X ½ nn.   b) ½ mm X ½ nn.   c) ½ Mm X ½ nn.   d) ½ Mm X ¼ nn.

A type of tomato (Solanum lycopersicum) produces fruit in three possible colors: red, green, and orange. You cross a true-breeding orange-fruited plant with a true-breeding green-fruited plant, and all the F1 offspring are red. You intercross the red F1s, and the resulting F2 generation consists of 108 red-, 40 orange-, and 44 green-fruited plants.   1) What type of epistasis is acting (dominant, recessive, duplicate dominant, or duplicate recessive)?    2) Assign the phenotypes to a modified 9:3:3:1 ratio. (Do not just calculate the actual ratio of the phenotypes.)  Red : _____Orange : _____Green: _____