When Allele Frequencies Stay Constant. Ch 14. Population Genetics. Genes can be considered at the POPULATION level. Population = An interbreeding group of the same species in a given geographical area
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A small change in ALLELE FREQUENCY is a MICROEVOLUTION, and over time, MACROEVOLUTION (the formation of a new species) can occur.
Hardy-Weinberg equilibrium provides a framework for understanding how populations evolve.
from generation to generation,
the population is in HARDY-
"The Hardy-Weinberg equation is based on Mendelian genetics. It is derived from a simple Punnett square in which p is the frequency of the dominant allele and q is the frequency of the recessive allele."The Hardy-Weinberg equation is used to predict genotype frequencies in a population.
Developed independently by an English mathematician and a German physician
Used algebra to explain how allele frequencies predict genotypic and phenotypic frequencies in a population of diploid, sexually-reproducing species
Disproved the assumption that dominant traits would become more common, while recessive traits would become rarer
(1/23)(1/23)(1/4) = 1/2000
Often q approaches 0 if a trait is rare enough, which makes the carrier frequency simply TWICE the frequency of the trait.
Differing number of copies of the same repeat migrate at different speeds on a gel
1) A blood sample is collected from suspect
2) White blood cells release DNA
3) Restriction enzymes cut DNA
4) Electrophoresis aligns fragments by size
5) Pattern of DNA fragments transferred to a nylon sheet
6) Exposed to radioactive probes
7) Probes bind to DNA
8) Sheet placed against X ray film
9) Pattern of bands constitutes DNA profile
10) Identify individuals