Suppose the genes for eye color and wing shape are both on the X chromosome (they are linked) and are known to be 68 map units apart. In a mating between a Xw+m+Xwm female and a XwmY male that produces 1000 progeny, how many recombinant progeny would you expect to observe?

Question

Biology

Franco Knox

8 September, 02:05

Suppose the genes for eye color and wing shape are both on the X chromosome (they are linked) and are known to be 68 map units apart. In a mating between a Xw+m+Xwm female and a XwmY male that produces 1000 progeny, how many recombinant progeny would you expect to observe?

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Answers (1)

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Sariah Newman · Answer 1

500

Explanation:

The greater the distance between two linked genes, the higher the chances of crossing over happening between them. If genes are in the same linkage group but separated by 50 or more map units, they will assort independently from each other during meiosis.

The female will produce the following gametes, each with a 1/4 proportion:

• Xʷ⁺ᵐ⁺ (parental)

• Xʷᵐ (parental)

• Xʷ⁺ᵐ (recombinant)

• Xʷᵐ⁺ (recombinant)

In an offspring of 1000 individuals, half of them are expected to be recombinant.

The maximum recombination frequency possible between 2 genes is 50%, because when a crossing over happens half the generated gametes will be parental and half will be recombinant.