# classical genetics problem - classical genetics (Jun/24/2007 )

Hi Friends does any one has an answer for this question...

A recombinant inbred line (RIL) population F10 of a self polinating crop consists of 400 individuals derived from a cross of one resistant parent with one susceptible parent. Three hundred of these lines were resistant to a pathogen strain one hundred of these lines were susceptible to the same strain. How many resistant genes are there in the resistant parent, why? What possible genotypes for the resistant lines and susceptible lines, why?

-niki-

This sounds suspiciously like a homework question...
I'm not going to just give you the answer, you're going to have to work a bit. I will tell you it's Mendelian (but you probably already know that...)
What are the important details? Do they fit with any of the standard Mendelian ratios of inheritance?

-swanny-

QUOTE (swanny @ Jun 24 2007, 05:55 PM)
This sounds suspiciously like a homework question...
I'm not going to just give you the answer, you're going to have to work a bit. I will tell you it's Mendelian (but you probably already know that...)
What are the important details? Do they fit with any of the standard Mendelian ratios of inheritance?

ratio is like is 3/1 looks like single gene but there are 10 generations

first cross is like RR x rr = RR Rr rr this is F1

only Rr will segratgate but also RR and rr will be carrried through crosses and how they will contribute to the ratio???

-niki-

You got the first.

Now comes some simple mathematics that astounds and befuddles biologist and embarrasses mathematicians, a basic quadratic equation which make up the Hardy-Weinberg Equilibrium

Tell me the what the Hardy-Weinberg Equilibrium is and its implicatioin.

-perneseblue-

This is HW equation

p² + 2pq + q² = 1

implication:By comparing genotype frequencies from the next generation with those of the current generation we can learn the rate for the selected trait...

F10

P= (RATIO OF RR IN F10)
2PQ=(RATIO OF rR IN F10)
Q=(RATION OF rr IN F10) is it okey to do it like this?

bUT HOW MANY R genes there are??

-niki-