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Problem.....Help!

Genetics as it applies to evolution, molecular biology, and medical aspects.

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Problem.....Help!

Postby uchiha_sasuke » Fri Mar 03, 2006 11:29 am

how do you solve this kind of problem? I never seem to have any idea on how to answer this. i even have no idea on how to make a punnet square on this problem. help me. onegai!

A normal visioned and bald woman whose father is bald and a mother who is red-green color blind marries a man who is nonbald but is red-green color blind.

a. What could be the probability that their children will be:
1. bald girls?
2. red-green color blind boys?
3. bald boys?
4. normal visioned girls?
5. nonbald and normal visioned girls and boys?
6. red-green color blind and bald boys and girls?
7. nonbald and red-green color blind boys and girls?
8. normal visioned and bald boys and girls?
b. Give the phenotypic ratio and genotypic ratio.
c. What could be the probability that they're children will be both normal to girls (in percent)?

please help me! i really have no idea on how to solve this!

sorry if i posted it here! but ireally need help with this problem and i noticed that a lot of people view general discussion than genetics(as far as i think it is) but do do do please help me!

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Postby 2810712 » Fri Mar 03, 2006 1:56 pm

A normal visioned and bald woman whose father is bald and a mother who is red-green color blind marries a man who is nonbald but is red-green color blind.

the bald woman i think has something harmone gene defect [ may be a mutation or a passed allele] along with the presence of baldness gene. i think now you can punnete it square if you know which is the dominant one or any other realtion in genes... you first have to have pedegree analysis done. The you get it thru punnetes.
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Postby MrMistery » Fri Mar 03, 2006 6:09 pm

The gene for baldness is recessive X linked, so that is why usually only men get it...
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Postby sham » Wed Mar 15, 2006 4:43 am

One possible solution (since both genes are sexlinked to the X chromosome and recessive).
R- dominant allele for normal vision
B - dominant allel for normal hair

Man (rB/Y) married woman (Rb/rB)
Gametes from man (rB and Y). Gametes from woman (Rb and rB).
Children genotypes will be female (Rb/rB and rB/rB) and male (Rb/Y and rB/Y)

Can get all probability from this except last question, i do not understand.

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Postby Remote » Sat Mar 18, 2006 7:57 am

MrMistery wrote:The gene for baldness is recessive X linked, so that is why usually only men get it...


I thought it was because it was sex influenced, not sex linked, that men were more likely to have pattern baldness.... a heterozygous male for pattern baldness is affected, whereas a heterozygous female for pattern baldness is not. If that's the case, then you'd have a dihybrid cross with the women homozygous recessive for baldness and heterozygous for colorblindness... the male would be homozygous dominant for baldness and hemizygous recessive for colorblindness. I'm just in my first genetics class so this may be completely wrong.... it's also almost 2am and I'm quite tired... but I tried. :)
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Postby MrMistery » Sat Mar 18, 2006 8:24 pm

We have a thread about baldness gene, some say it is sex linked, others say it is sex influenced. Anyway, it doesn't really matter. It is simply an example.
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Postby Remote » Sun Mar 19, 2006 10:12 pm

that's interesting... my textbook uses patern baldness as the main example for sex influenced genes
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Postby prematureejaculation » Mon May 14, 2012 4:58 am

I'm not really sure about the result but I guess it is on the choices that you have made. But there are some cases that the child will not get bald or even get color blind even if his or her parents have that kind of characters. If it is really on their blood line either both parents then you should expect one or both characters will be inherited.
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