okay... i know sum ppl were explaining on mirc last night but im still having dillemmas..
i read the text book stuff some more.. and here is my problem:
so female = xx male = xy
If there is a deficiency it is almost always on the x chrom..... (eg haemophilia) females having 2 x chroms will have a second gene to 'fall' back on if one is deficient. it is rare that both alleles are deficient... however for males a deficiency in a non-sexual gene on the x chrom may be disastrous. males only have one gene for that characteristic becuase they only have one x chrom andif that gene is deficient problems will arise... eg haemophilia... (stuff from text)
thats all good but problem: why cant the male 'fall' back on the y chrom??? this is not making sense to me. what is so special about the x chrom in the female that makes it a 'fall' back gene?
if any1 can clear up my dramas it would be much appreciated!
i read the text book stuff some more.. and here is my problem:
so female = xx male = xy
If there is a deficiency it is almost always on the x chrom..... (eg haemophilia) females having 2 x chroms will have a second gene to 'fall' back on if one is deficient. it is rare that both alleles are deficient... however for males a deficiency in a non-sexual gene on the x chrom may be disastrous. males only have one gene for that characteristic becuase they only have one x chrom andif that gene is deficient problems will arise... eg haemophilia... (stuff from text)
thats all good but problem: why cant the male 'fall' back on the y chrom??? this is not making sense to me. what is so special about the x chrom in the female that makes it a 'fall' back gene?
if any1 can clear up my dramas it would be much appreciated!