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Genetic/statistics help needed..

Syringer

Lifer
Aug 2, 2001
19,333
3
71
I don't get how to calculate the 2nd/3rd gens for models..how does one do it?

"Suppose that the prob of the genotypes, AA, Aa, aa are p, 2q, and r, respectively, in the first generation. Find the prob in the 2nd and 3rd gen, and show that they are the same."
 

Zee

Diamond Member
Nov 27, 1999
5,171
3
76
depends, are we examining the genes of a normal animal, plant or a spider?
 

Scouzer

Lifer
Jun 3, 2001
10,358
5
0
lots of punnets squares is the only way i learned...

BTW: What class is this for?
 

nmcglennon

Golden Member
Jul 19, 2002
1,170
0
0
use the hardy weinburg equation.
p^2 +2pq+q^2 = 1

Your probabilities will always equal 1.

p^2 is the probability of genotype AA
pq is the probability of genotype Aa
q^2 is the probability of genotype aa

Note Hardy Weinberg does not apply to cases of Genetic Drift, Nat. Selection, Mutation, Mieotic Drive, Gene Flow, etc.
try Googling for the Hardy Weinberg Equilibrium
 

nmcglennon

Golden Member
Jul 19, 2002
1,170
0
0
I think you are supposed to show change in the gene pool.

"A population in Hardy-Weinberg equilibrium shows no change. What the law tells us is that populations are able to maintain a reservoir of variability so that if future conditions require it, the gene pool can change. If recessive alleles were continually tending to disappear, the population would soon become homozygous. Under Hardy-Weinberg conditions, genes that have no present selective value will nonetheless be retained."

You still have the same number of genes (same number of a and same number of A), but you have a diff proportion of AA, Aa, aa. These change through generations, and you can calculate them... I had to do it in my genetics class last semester.
 

Syringer

Lifer
Aug 2, 2001
19,333
3
71
Originally posted by: nmcglennon
use the hardy weinburg equation.
p^2 +2pq+q^2 = 1

Your probabilities will always equal 1.

p^2 is the probability of genotype AA
pq is the probability of genotype Aa
q^2 is the probability of genotype aa

Note Hardy Weinberg does not apply to cases of Genetic Drift, Nat. Selection, Mutation, Mieotic Drive, Gene Flow, etc.
try Googling for the Hardy Weinberg Equilibrium

How does that apply with 3 variables?
 

Syringer

Lifer
Aug 2, 2001
19,333
3
71
Originally posted by: Syringer
Originally posted by: nmcglennon
use the hardy weinburg equation.
p^2 +2pq+q^2 = 1

Your probabilities will always equal 1.

p^2 is the probability of genotype AA
pq is the probability of genotype Aa
q^2 is the probability of genotype aa

Note Hardy Weinberg does not apply to cases of Genetic Drift, Nat. Selection, Mutation, Mieotic Drive, Gene Flow, etc.
try Googling for the Hardy Weinberg Equilibrium

How does that apply with 3 variables?

Does that mean I can subsititute p for p^2, q for pq, and q for q^2?