Biology Forum › Genetics › Question
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- March 12, 2007 at 2:19 am #7147Melly1657Participant
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
- March 12, 2007 at 2:51 am #69930Melly1657Participant
please help answer this question!
- March 12, 2007 at 4:30 am #69931LilKimParticipant
your question is missing a few details… is this an X linked, Y linked, recessive or dominant inheritance?
- March 13, 2007 at 1:10 pm #699802LoulaParticipant
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.
- March 13, 2007 at 1:36 pm #69981loveangelParticipant
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..
- March 13, 2007 at 1:40 pm #69982loveangelParticipant
there’s this process to find the answer, the cross pollination.
- March 13, 2007 at 8:53 pm #69987RevengedParticipantquote 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…
- March 13, 2007 at 8:55 pm #69988RevengedParticipantquote 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…
- March 13, 2007 at 11:48 pm #69992Dr.SteinParticipantquote loveangel:there’s this process to find the answer, the cross pollination.
Pollination? 😕
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