Question

31. In mice, Agouti coat color (A) is dominant to a mutation giving black coat color (a). The expected genotypic ratio for the cross heterozygous Agouti (Aa) X heterozygous Agouti (Aa) is CORRECTLY shown as A) 1:2:1 D) 3:1 B) 1 AA: 2 Aa : 1 aa E) more than one above C) 3 Agouti : 1 black :

Answer 1

The correct genotypic ratio for the cross of heterozygous Agouti mice (Aa x Aa) is 1 AA : 2 Aa : 1 aa, in accordance with Mendelian genetics.

Step-by-step explanation:

In terms of Mendelian genetics, the cross between two organisms with the heterozygous genotype for a certain trait (in this case, coat color in mice), often results in a genotypic ratio of 1:2:1. This stands for 1 homozygous dominant (AA), 2 heterozygous dominant (Aa), and 1 homozygous recessive (aa).

To illustrate this, a Punnett square helps visualize the distribution of parental alleles to offsprings. When crossing two heterozygous Agouti mice (Aa x Aa), it results in:

• 1 mouse with genotype AA
• 2 mice with genotype Aa
• 1 mouse with genotype aa

Therefore, option B) 1 AA: 2 Aa : 1 aa is the correct genotypic ratio for the cross of heterozygous Agouti mice.

Learn more about Mendelian genetics