Question

In dogs a loud bark(B) is dominant over a soft bark(b). Also, a long coat (L ) is dominant to a short coat(l). Show a cross between a heterozygous loud, heterozygous long coat dog and another heterozygous loud, heterozygous long coat dog.

Answer 1

The Punnett square for the cross between a heterozygous loud, heterozygous long coat dog and another heterozygous loud, heterozygous long coat dog would be:

| L l

---------------

B | BL | B l |

b | bL | bl |

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Each box in the Punnett square represents a possible offspring genotype. The letters on the top and left side of the square represent the alleles from one parent, and the letters on the top and bottom represent the alleles from the other parent.

From the Punnett square, we can see that there are four possible genotypes for the offspring: BL, B l, bL, and bl. The uppercase letters represent the dominant traits (loud bark and long coat), and the lowercase letters represent the recessive traits (soft bark and short coat).

The ratio of genotypes in the offspring is 1 BBLL : 2 BBLl : 1 BbLL : 2 BbLl : 1 bbLL : 2 bbLl : 1 bbl.

The ratio of phenotypes in the offspring is 3 loud, long coat : 3 loud, short coat : 1 soft, long coat : 1 soft, short coat.