In mice, yellow color (A) dominates over black (a). What splitting by phenotype and genotype will be in F1 when two yellow mice are crossed, given that the A allele in the homozygous state causes embryo death?
Viable mice with yellow hair will be heterozygotes – Aa. They will produce germ cells of two types: a and A.
When crossing such mice with each other, we obtain offspring of the following type:
25% of mouse embryos conceived by this pair of individuals will be AA, which will cause their death;
50% of the mice will have a yellow coat color (Aa);
25% of the mice will have black coat (aa).
Answer: the splitting in the offspring of yellow mice will be 2: 1, both by genotype and phenotype.
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