genetics help asap 2. In swine, the color of hair is white, sandy, or red. Red h

Question

genetics help asap

2. In swine, the color of hair is white, sandy, or red. Red hair (B) is dominant to white (b), while the unlinked recessive allele a is epistatic to (over-rides) red or white, causing sandy hair. A sandy boar was bred twice. Three piglets from a red sow were nsady andwhie threilets from a white sow were also red, andy, and A. List the possible genotypes for each hair phenotype in swine. Red White Sandy B. What were the genotypes of all three parents? Red sow White sow Sandy boar

Explanation / Answer

Here Red (B) is dominant over White (b) and recessive allele ‘a’ is epistatic to Red and White.

Note: The dominant allele could be express either as homozygous (BB) or heterozygous (Bb) condition, the recessive allele will only express in homozygous (bb) condition and the epistatic allele will express in homozygous recessive condition (aa) only.

A. Possible genotypes of different colors of swain would be:

Red:          BB AA, BB Aa, Bb AA, BbAa

    Genotype for Red hair are the combination of alleles for red phenotype (BB,Bb ) and nonrecessive epistatic alleles (AA,Aa).

White:      bbAA, bbAa

     Genotype for White hair are the combination of alleles for white phenotype (bb ) and nonrecessive epistatic alleles (AA,Aa).

Sandy:    bbaa, Bbaa, BBaa.

    Genotype for Sandy hair are the combination of alleles for red (BB,Bb ) or white (bb) phenotype with recessive epistatic alleles (aa).

B. A sandy bore was breaded with red sow and white sow, in both cases red white and sandy piglets were prodused.

So red sow (parents) genotype should be BbAa

Only the heterozygous genotype Bb could give all phenotypes in offspring by crossing with either of Bb, bb allele containing boars.

Note: For above reason the allele BB should not be present in boar.

And only the Aa genotype could give both sandy (aa) and non sendy (AA, Aa) piglets by breading with sandy boar (aa).

The white sow (parents) should have genotype bbAa. (white sow should have bb allele because white is resseve and epistatic allele should be Aa because it able to give both sandy and non sandy phenotype)

The sandy boar (parents) should have phenotype Bbaa. (boar should not have BB as previous note, and not also bb beacouse it could not give rerphenotype with either sow)

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