destroyer bio #298

[IWantH2O]

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why did he assume that he got the normal x from the mother when there is a 50% of gettin the colorblind x as well?

 

[tuthluver]

A male child can only receive the X from the mother b/c he recieves the Y from the father and also men cannot be just a carrier for colorblindness since it is a X-linked trait. If they have the gene; they express it since men only have 1 X chromosome.

 

[IWantH2O]

A male child can only receive the X from the mother b/c he recieves the Y from the father and also men cannot be just a carrier for colorblindness since it is a X-linked trait. If they have the gene; they express it since men only have 1 X chromosome.

ya but no were in the problem did it say that the man is normal....so why did we assume he was

 

[futuredent22]

ya but no were in the problem did it say that the man is normal....so why did we assume he was

You don't assume he is normal. The question asks what is the chance that his MALE child will be colorblind. Since the man gives his Y chromosome to his son, it doesn't matter whether he is colorblind because is X chromosome never comes into play. The son's X will come from his mother, who is normal, so there is 0 chance the son will be colorblind.

 

[tuthluver]

👍Emoryeagle, thanks for explaining that for me...

 

[acupofchai]

if the mother is normal how do you know she's not a carrier?

 

[yakuza]

if the mother is normal how do you know she's not a carrier?

I usually assume shes normal XX unless it states her mom or dad had something.