ATAR Notes: Forum

Uni Stuff => Universities - Victoria => University of Melbourne => Topic started by: zibb3r on August 17, 2014, 01:22:35 am

Title: MATHS FOR BIOMEDICINE
Post by: zibb3r on August 17, 2014, 01:22:35 am
This week's assignment (#2); is it just me, or is it really weird????

Are the difference equations for f^a(n+1) and f^A(n+1) reversed???  How do you do it?
Title: Re: MATHS FOR BIOMEDICINE
Post by: Limista on August 17, 2014, 10:08:01 am
This week's assignment (#2); is it just me, or is it really weird????

Are the difference equations for f^a(n+1) and f^A(n+1) reversed???  How do you do it?

What do you mean by 'reversed'? If you mean f^a(n+1) = 1- f^A(n+1), then yes you are correct.

How to do it --> calculate allele frequency of fa(n+1) from genotype frequency of faa(n+1) = p^2 according to hardy-weinburg

To get faa(n+1), refer back to the irreversible mutation lecture slides from week 2 (or wk 3, can't remember) that has the answer on it. 

You should find that fa(n+1) = p after solving the difference equation.  :)
Title: Re: MATHS FOR BIOMEDICINE
Post by: zibb3r on August 17, 2014, 11:56:53 am
What do you mean by 'reversed'? If you mean f^a(n+1) = 1- f^A(n+1), then yes you are correct.

How to do it --> calculate allele frequency of fa(n+1) from genotype frequency of faa(n+1) = p^2 according to hardy-weinburg

To get faa(n+1), refer back to the irreversible mutation lecture slides from week 2 (or wk 3, can't remember) that has the answer on it. 

You should find that fa(n+1) = p after solving the difference equation.  :)

Thanks Starfish!  Because  it is a recessive gene mutating to a dominant gene (a --> A) wont fa(n+1)=(1-u)fa(n) and fA(n+1)=(1-u)fA(n)+u????

Which is essentially the opposite of what is said in the lectures?  Because in the lectures they used a dominant gene mutating to a recessive gene (A --> a)?

Thanks :) :) :)
Title: Re: MATHS FOR BIOMEDICINE
Post by: Limista on August 17, 2014, 01:47:09 pm
Thanks Starfish!  Because  it is a recessive gene mutating to a dominant gene (a --> A) wont fa(n+1)=(1-u)fa(n) and fA(n+1)=(1-u)fA(n)+u????

Which is essentially the opposite of what is said in the lectures?  Because in the lectures they used a dominant gene mutating to a recessive gene (A --> a)?

Thanks :) :) :)

yup that's completely correct!

Oh yes, I acknowledge that was the reverse. But the idea was the same - you just had to switch around the alleles being mutated & realise that this is an irreversible mutation (instead of reversible). Let's face it though, we were pretty much copying the lecture slide in answering this question  :P
Title: Re: MATHS FOR BIOMEDICINE
Post by: zibb3r on August 17, 2014, 02:29:29 pm
yup that's completely correct!

Oh yes, I acknowledge that was the reverse. But the idea was the same - you just had to switch around the alleles being mutated & realise that this is an irreversible mutation (instead of reversible). Let's face it though, we were pretty much copying the lecture slide in answering this question  :P

Thanks so much :D  Can I ask what you wrote about 1C?  It seems like such a broad question?!
Title: Re: MATHS FOR BIOMEDICINE
Post by: Limista on August 17, 2014, 05:03:00 pm
Thanks so much :D  Can I ask what you wrote about 1C?  It seems like such a broad question?!

Answer to this is also in the lecture notes. Do you remember when Anthony talked about how HW only applies to a single randomly mating population? He used the countries in the table to explain this..look it up  :)