genetics problem

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

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biohelp22
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genetics problem

Post by biohelp22 » Sun Apr 23, 2006 3:32 pm

these things always stump me

in cows, eye color is controlled by a single gene with two alleles. when a homozygous cow with brown eyes is crossed with a homozygous cow with green eyes, cows with blue eyes are produced. if the blue-eyed cows are crossed with each other, what fraction of their offspring will have brown eyes

-0
-1/4
-1/2
-3/4
-1

i attemped to do this problem but i got completely lost...but im going to say 1/2

risingstar5
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Post by risingstar5 » Sun Apr 23, 2006 5:36 pm

i got 1/4

because if you cross BB (brown eyes) with bb (green eyes) the blue eyed cows would be Bb
so if you cross the two blue eyed cows (Bb x Bb) then only 1/4 of those would be BB (brown eyes)

i hope that helped and i hope its right!! ;)
Never let the odds keep you from pursuing what you know in your heart you were meant to do. <3

biohelp22
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Post by biohelp22 » Sun Apr 23, 2006 6:08 pm

oh i get it
that makes so much sense now

rg
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Post by rg » Fri May 05, 2006 6:54 pm

this question cant be solved until it is mentioned which one is dominant and which one is recessive..

kiekyon
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Post by kiekyon » Mon May 08, 2006 7:20 am

rg wrote:this question cant be solved until it is mentioned which one is dominant and which one is recessive..


i dont think this is a dominant/recessive casa here..

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opuntia
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Post by opuntia » Mon May 08, 2006 1:57 pm

If both are homozygous, then one should be dominant over the other... :? :? so in here also the same thing must happen...
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kiekyon
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Post by kiekyon » Fri May 12, 2006 9:05 am

XX=brown
Xx=blue
xx=green

Xx crossed= 1XX:2Xx:1xx
for brown eye(XX)= 1/4

so, no dominant gene here
there are codominant :roll:

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Post by oana_t » Sun Jun 11, 2006 7:51 pm

the answer is 1/4.because u get 25% AA(brown) and 50 % Aa(brown also).

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