Question

In horses, the Overo gene, Ov, produces a white splotch pattern on the coat. The overo phenotype is seen only when a horse has one Ov copy, Ovov. Horses with two Ov copies, OvOv, die soon after birth and are called white overo because they are completely white. Horses with no Ov copies are solid colored, ovov. The Leopard complex gene, Lp, shows incomplete dominance and controls white spotting. One Lp allele, Lplp, produces the leopard phenotype, in which there are spots everywhere. Two Lp alleles, LpLp, produce the fewspot phenotype, in which the horse is mostly white with colored spots. A horse that is both overo and leopard is called pintaloosa, and these horses are spotted with splotches. A horse that is overo and fewspot is considered fewspot because the white areas from Lp is indistinguishable from the white from Ov. Horse with overo phenotype. Overo Horse with solid coloration. Solid Horse with leopard phenotype. Leopard Horse with pintaloosa phenotype. Pintaloosa Horse with fewspot phenotype. Fewspot Suppose that 16 pairs of pintaloosa horses have one offspring per pair. How many of each phenotype would be expected

Answer 1

The question is incomplete. Here is the complete question.

In horses, the Overo gene, Ov, produces a white splotch pattern on the coat. The overo phenotype is seen only when a horse has one Ov copy, Ovov. Horses with two Ov copies, OvOv, die soon after birth are called white overo because they are completely white. Horses with no Ov copies are solid colored, ovov.

The Leopard complex gene, Lp, shows incomplete dominance and controls white spotting. One Lp allele, Lplp, produces the leopard phenotype, in which there are spots everywhere. Two Lp alleles, LpLp, produce the fewspot phenotype, in which the horse is mostly white with colored spots.

A horse that is both overo and leopard is called pintaloosa, and these horses are spotted with splotches. A horse that is overo and fewspot is considered fewspot because the white areas from Lp is indistinguishable from the white from Ov.

Suppose that 16 pairs of pintaloosa horses have one offpring per pair. How many each phenotype would be expected? Determine the number out of 16 expected for each phenotype. Only count phenotypes of offspring expected to live past one week of age.

overo:

white overo:

fewspot:

Answer: Overo: 2

              White overo: 0

              Fewspot: 3

Explanation: Pintaloosa is a "combination" of overo and leopard, so the pair's genotype is OvovLplp.

To cross a pair, use Punnet Square and to facilitate, use the square for each characteristics:

Punnett Square For overo and white overo:

          Ov             ov

Ov    OvOv        Ovov

ov    Ovov          ovov

Analysing this Punnett square, notice that there are 2 individuals who will carry the genotype for overo (Ovov) phenotype. So, 2 out of the 16 pair will have an overo phenotype.

Since white overo is recessive (ovov) and doesn't survive past birth, there will be zero horses with that phenotype.

Punnett Square For leopard and fewspot:

          Lp         lp

Lp    LpLp      Lplp

lp     Lplp       lplp

From this square, notice that there are 1 individual who is fewspot. However, a horse that is overo and fewspot is considered fewspot, so for the 16 pair, 3 out 16 will be fewspot.