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Genetic Variations within Populations 11.1

Genetic variation Lots of genotypes means more phenotypes More phenotypes means increased likelihood of survival if something changes What kinds of changes are we talking about?

Gene Pools Combined alleles of all the individuals in a population

Allele frequency How common a certain allele is in a population

Calculating Allele Frequencies Top of page 329

Calculating Allele Frequencies (# of specific allele/# in pop.) x 100 There are 10 alleles for long hair in a population of 30 total snurfles (10 long hair alleles/30 total) x 100 (10/30) x 100 (.3333) x 100 = 33.33%

Practice!!! Snurfles!!! HH or Hh = long hair, hh = no hair There is a population of 50 snurfles. 25 are homozygous dominant for long hair, 10 are heterozygous, and 15 are homozygous recessive. Find the allele frequency for the long hair allele AND the short hair allele

Practice Our snurfles have migrated to a new environment and have much more space. More space means for snurfles!!! After a few years of getting busy we have 123 snurfles are homozygous dominant, 78 heterozygous, and 38 are homozygous recessive This is the same set of snurfles from the previous problem, so the same allele rules apply!!!