Population genetics problems

Population genetics problems - POPULATION GENETICS AND THE...

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POPULATION GENETICS AND THE HARDY-WEINBERG PRINCIPLE The Hardy-Weinberg formulas allow scientists to determine whether evolution has occurred. Any changes in the gene frequencies in the population over time can be detected. The principle essentially states that if no evolution is occurring, then an equilibrium of allele frequencies will remain in effect in each succeeding generation of sexually reproducing individuals. In order for H-W equilibrium to remain (i.e. no evolution is occurring) the following five conditions must be met: 1. No mutations must occur so that new alleles do not enter the population. 2. No gene flow can occur (i.e. no migration of individuals into, or out of, the population). 3. Random mating must occur (i.e. individuals must pair by chance) 4. The population must be large so that no genetic drift (random chance) can cause the allele frequencies to change. 5. No selection can occur so that certain alleles are not selected for, or against. Obviously, the Hardy-Weinberg equilibrium cannot exist in real life. Some or all of these types of forces all act on living populations at various times and evolution at some level occurs in all living organisms. The Hardy-Weinberg formulas allow us to detect some allele frequencies that change from generation to generation, thus allowing a simplified method of determining that evolution is occurring. There are two formulas that must be memorized: p 2 + 2pq + q 2 = 1 and p + q = 1 p = frequency of the dominant allele in the population q = frequency of the recessive allele in the population p 2 = percentage of homozygous dominant individuals q 2 = percentage of homozygous recessive individuals
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This note was uploaded on 04/30/2011 for the course BIOL 1362 taught by Professor Loeblich during the Spring '08 term at University of Houston.

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Population genetics problems - POPULATION GENETICS AND THE...

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