Cross palomino X palomino chestnut X chestnut cremello X cremello palomino X chestnut palomino X cremello chestnut X cremello
13 palomino, 6 chestnut, 5 cremello 16 chestnut 13 cremello
8 palomino, 9 chestnut 11 palomino, 11 cremello 23 palomino
15. If there are five alleles at a locus, how many genotypes may there be at this locus? How many different kinds of homozygotes will there be? How many genotypes and homozygotes would there be with eight alleles?
16. Turkeys have black, bronze, or black-bronze plumage. Examine the results of the following crosses:
(a) Explain the inheritance of the palomino, chestnut, and cremello phenotypes in horses.
(b) Assign symbols for the alleles that determine these phenotypes, and list the genotypes of all parents and offspring given in the preceding table.
The LM and LN alleles at the MN blood group locus exhibit codominance. Give the expected genotypes and phenotypes and their ratios in progeny resulting from the following crosses.
In the pearl millet plant, color is determined by three alleles at a single locus: Rp1 (red), Rp2 (purple), and rp (green). Red is dominant over purple and green, and purple is dominant over green (Rp1 > Rp2 > rp). Give the
Cross 1: black and bronze Cross 2: black and black Cross 3: black-bronze and black-bronze Cross 4: black and bronze
Cross 5: bronze and black-bronze Cross 6: bronze and bronze
Offspring all black
3/4 black, 1/4 bronze all black-bronze
1/2 black, 1/4 bronze, 1/4 black-bronze 1/2 bronze, 1/2 black-bronze
3/4 bronze, 1/4 black-bronze
Do you think these differences in plumage arise from incomplete dominance between two alleles at a single locus? If yes, support your conclusion by assigning symbols to each allele and providing genotypes for all turkeys in the crosses. If your answer is no, provide an alternative explanation and assign genotypes to all turkeys in the crosses.
17. In rabbits, an allelic series helps to determine coat color: C (full color), c°h (chinchilla, gray color), ch (himalayan, white with black extremities), and c (albino, all white). The C allele is dominant over all others, c°h is dominant over ch and c, ch is dominant over c, and c is recessive to all the other alleles. This dominance hierarchy can be summarized as C > c°h > ch > c. The rabbits in the following list are crossed and produce the progeny shown. Give the genotypes of the parents for each cross:
expected phenotypes and ratios of offspring produced by
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