In dogs, the black color of the coat dominates the coffee, and the short coat dominates the long coat. Both pairs of genes are on different chromosomes. The hunter bought a black short-haired dog and wants to be sure that his dog is purebred. What breeding partner does he need to choose to ensure the breed is clean? Write down the possible genotypes of the hunter dog and the possible variants of cleavage by genotype and phenotype when crossing, with which you will check its genotype.
1) A – black wool, a – coffee wool B – short hair, b – long wool Possible genotypes: AaBb, AaBB, AABB, AABB.
2) It is necessary to cross with a recessive homozygote for both genes (a long-haired dog with coffee-colored hair). It will be an analyzing cross.
3) Only in the case when there will be signs of splitting in the offspring can we talk about the pure breed of the acquired dog
Aabb x aabb
100% black shorthair
The other three options suggest that the dog is not a “clean line”
– AaBb x aabb
It will turn out 1: 1: 1: 1 AAB: Aabb: aaBb: aabb (black shorthair: black long-haired: coffee shorthair: coffee long-haired)
– AaBB x aabb
It will turn out 1: 1 AaBb: aaBb (black shorthair: coffee shorthair)
– AABb x aabb
Get 1: 1 AaBb: Aabb (black shorthair: black longhair)
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