Question

. Jake made a deal with his father-in-law, Fred. They divided up Fred’s flock so that Jake got all the spotted goats and black sheep, while Fred got all the solid colored goats and white sheep. They agreed that whenever a spotted goat or black sheep appeared in Fred’s flock he would give it to Jake; and whenever a solid goat or a white sheep appeared in Jake’s flock he would give it to Fred. As time passed, Jake had to keep giving some of his flock to Fred, but Fred didn’t have to give any of his flock to Jake. Explain why using genetics.

Answer 1

The possible reason can be, spotted color in goat and black color in sheep are dominant characters, whereas, solid color in goat and white color in sheep are recessive characters. It may happen that some of the goat and sheep that Jake got are heterozygous dominant. As a result of this, some of their offspring have the recessive traits. This can be understood by the following cross-

Let the genotype of spotted goat and black sheep be Ss and Bb, respectively. The cross between two spotted goats is shown below-

	S	s
S	SS	Ss
s	Ss	ss

Genotype and phenotype of the resulting offsprings are- SS (Spotted goat), Ss (Spotted goat) and ss (solid colord goat). Thus, 25% possibility is there that solid colored goat will be produced.

Similarly, the cross between black sheep is shown below-

	B	b
B	BB	Bb
b	Bb	bb

Genotype and phenotype of the resulting offsprings are- BB (Black sheep), Bb (black sheep) and bb (white sheep). Thus, 25% possibility is there that white sheep will be produced.

Thus, Jake had to give some of his flock to Fred. In case of Fred's flock, neither spotted goat nor black sheep would appear. Solid color in goat and white color in sheep, both are homozygous recessive traits, and therefore, they will never produce offsprings having dominant characters. Thus, Fred did not have to give any of his flock to Jake.