The dorsal pigment pattern of frogs can be either 'leopard' (white pigment between dark spots) or 'mottled' (pigment between spots appears mottled). The trait is controlled by an autosomal gene. Males and females are selected from pure-breeding populations, and a pair of reciprocal crosses is performed. The cross results are shown below.

        Cross 1:    P₁: Male leopard x male mottled
                          F₁: All mottled
                          F₂: 70 mottled, 22 leopard
        Cross 2:    P₁: Male mottled x female leopard
                          F₁: All mottled
                          F₂: 50 mottled, 18 leopard

In the F₂ progeny from both crosses, what proportion is expected to be homozygous? What proportion is expected to be heterozygous?

The dorsal pigment pattern of frogs can be either 'leopard' (white pigment between dark spots) or 'mottled' (pigment between spots appears mottled). The trait is controlled by an autosomal gene. Males and females are selected from pure-breeding populations, and a pair of reciprocal crosses is performed. The cross results are shown below.

        Cross 1:    P₁: Male leopard x male mottled
                          F₁: All mottled
                          F₂: 70 mottled, 22 leopard
        Cross 2:    P₁: Male mottled x female leopard
                          F₁: All mottled
                          F₂: 50 mottled, 18 leopard

Propose two different genetic crosses that would allow you to determine the genotype of one mottled frog from the F₂ generation.

The dorsal pigment pattern of frogs can be either 'leopard' (white pigment between dark spots) or 'mottled' (pigment between spots appears mottled). The trait is controlled by an autosomal gene. Males and females are selected from pure-breeding populations, and a pair of reciprocal crosses is performed. The cross results are shown below.

        Cross 1:    P₁: Male leopard x male mottled
                          F₁: All mottled
                          F₂: 70 mottled, 22 leopard
        Cross 2:    P₁: Male mottled x female leopard
                          F₁: All mottled
                          F₂: 50 mottled, 18 leopard

Compare and contrast the results of the reciprocal crosses in the context of autosomal gene inheritance.

The dorsal pigment pattern of frogs can be either 'leopard' (white pigment between dark spots) or 'mottled' (pigment between spots appears mottled). The trait is controlled by an autosomal gene. Males and females are selected from pure-breeding populations, and a pair of reciprocal crosses is performed. The cross results are shown below.

        Cross 1:    P₁: Male leopard x male mottled
                          F₁: All mottled
                          F₂: 70 mottled, 22 leopard
        Cross 2:    P₁: Male mottled x female leopard
                          F₁: All mottled
                          F₂: 50 mottled, 18 leopard

Which of the phenotypes is dominant? Explain your answer.

A male mouse from a true-breeding strain of hyperactive animals is crossed with a female mouse from a true-breeding strain of lethargic animals. (These are both hypothetical strains.) All the progeny are lethargic. In the F₂ generation, all offspring are lethargic. What is the best genetic explanation for these observations? Propose a cross to test your explanation.

Black skin color is dominant to pink skin color in pigs. Two heterozygous black pigs are crossed.

If these pigs produce a total of three piglets, what is the probability that two will be pink and one will be black?