Biology Help!!. need help with biology. pls help!!. its urgent. i will give full 5 stars?

suppose that an allele, d, of a sex-linked gene is recessive and lethal. A man marries a woman who is heterozygous for this gene. If the couple had many normal children, what would be the predicted sex ratio of these children?

Base your response on the number of predicted living children

- Genotypes of the parents 

- Gene combination for the gametes of each parent

- A completed punnett square

- Genotype ratio of offspring (prediction)

- Phenotype ratio of offspring (prediction)

2 Answers

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  • 1 month ago

    XD Y x XD Xd =>

    XD XD normal female

    XD Xd carrier female

    XD Y normal male

    Xd Y dead male

    Predicted sex ratio of living offspring:

    2 female : 1 male

  • 1 month ago

    Not 100% confident but you have

    Male                     Female

    DD                            Dd

    Gives you

    D  D                     D    d     gene options

    So if you cross those you get

    DD  Dd   DD  Dd

    so that means you're looking at a 1:1 ratio for getting a boy or girl, as the recessive gene is female-only (sex-linked)

    There is a 100% chance any female will be a carrier (heterozygous) for the gene

    I hope this helps

    Source(s): Completed A level biology, I'm reaching back a couple of years but I do remember doing this
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