Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Hardy-Weinberg Equation

  1. Apr 8, 2010 #1
    1. The problem statement, all variables and given/known data
    Apply the Hardy-Weinberg equation to estimate the incidence of "carriers" in the population you surveyed and in the populations you researchered.

    I've found out that being Lactose Intolerant is a recessive trait and that 60% of the worlds population is lactose intolerant. That means that 30% are tolerant and are either homozygous dominant or heterozygous.

    I was not a school for over a week and was given this as an assignment. I have never heard of this equation or even practised it before. Its due tomorrow, no exceptions because she needs marks so i cant ask for clarification. Im not looking for the answer just someone to lay out the steps involved and offer assistance. Please and Thank you!

    2. Relevant equations
    p2 + 2pq + q2 = 1
    p + q = 1

    3. The attempt at a solution
    I dont even know where to begin.
  2. jcsd
  3. Apr 8, 2010 #2


    User Avatar
    Homework Helper
    Gold Member

    You seem to know what dominant, heterozygous, homozygous mean.

    I suppose you know what a carrier is - someone who can transmit the (intolerance) trait to progeny but does not him/her self suffer from it. So what would be their genetic constitution?

    p is the gene (or allele) frequency or fraction in the population. e.g. of the gene associated with a given character, e.g. lactose intolerance, call that allele l. q (which = (1 - p) ) is the frequency of the alternative allele, call the allele L.

    So as each individual in the population has a pair of genes, what, in terms of p and q will be the fraction of ll, lL, and LL in the population? If you are given the numerical value of one of these fractions can you work out the one you want to know? Frankly it's almost common sense not rocket science even if you missed a lesson.
    Last edited: Apr 9, 2010
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook