Biology Forum Genetics Question

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    • #7147
      Melly1657
      Participant

      A female who does not carry the color blindness allel has children with a male who is color blond. What proportion of their children will be colorblind? all- 1/4-1/2-or 3/4

    • #69930
      Melly1657
      Participant

      please help answer this question!

    • #69931
      LilKim
      Participant

      your question is missing a few details… is this an X linked, Y linked, recessive or dominant inheritance?

    • #69980
      2Loula
      Participant

      Colour Blindness is an X-linked recessive trait. If a female has normal vision, and to have colour-bind children, she would either have to be a carrier of the recessive gene, and/or be married to a colour blind male.

      For example, a cross between a colour-blind male (XrY) and a normal vision woman who is a carrier (XRXr) could have four possible offspring combinations.

      1. Colour-blind male(XrY) – 1/4 or 25%
      2. Normal Vision Boy(XRY) – 1/4 or 25%
      3. Colour-blind female(XrXr) – 1/4 or 25%
      4. Normal Vision Female carrier (XRXr) – 1/4 or 25%

      However, since it is a sex-linked disease carried on the X chromosome, if the female does not have the colour-blindness allele at all, there is no way any of her children will be colourblind (though any female daughters will be carriers).

      I hope this helps.

    • #69981
      loveangel
      Participant

      the female needs 2 allele to inherit the colorblindness or baldness, while the male only needs 1…

      but if their offspring is a female, then there’s a possibility that the female offspring will be a carrier..

    • #69982
      loveangel
      Participant

      there’s this process to find the answer, the cross pollination.

    • #69987
      Revenged
      Participant
      quote Melly1657:

      A female who does not carry the color blindness allel has children with a male who is color blond. What proportion of their children will be colorblind? all- 1/4-1/2-or 3/4

      Colour blindness is a X-linked recessive condition…

      In this case the parents alleles are:

      Mother : XX (not a carrier) vs. Father: XcY (sufferer of disease)

      Offspring with be:

      2 x Female carriers (XcX)
      2 x Normal Males (XY)

      So none of your answers are correct… In this case, none of the children would be colour blind…

    • #69988
      Revenged
      Participant
      quote 2Loula:

      However, since it is a sex-linked disease carried on the X chromosome, if the female does not have the colour-blindness allele at all, there is no way any of her children will be colourblind (though any female daughters will be carriers).

      Yes, exactly…

    • #69992
      Dr.Stein
      Participant
      quote loveangel:

      there’s this process to find the answer, the cross pollination.

      Pollination? 😕

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