ANTH 105 Lecture Notes - Lecture 7: Sickle-Cell Disease, Allele Frequency, Point Mutation
Document Summary
Natural selection acts on some individual in population. Links ideas of darwin and mendel with modern dna. Change in allele frequencies from one generation to the next. Change in allele frequencies expected to result in speciation. 4 key factors can be seen as underlying change over time/ evolution. Among primary sources for new variation on which evolution acts. For evolution to act on any given mutation, it must occur in which type of cell: Random: no purpose happens naturally but can be neutral, harmful, or helpful. Evolution acts on harmful and helpful mutations by increasing or decreasing allele frequencies in later genes. Changes in genetic code reflecting simple base pair changes. Caused by a point mutation that changes a single amino acid leading to cell failure. To structure of the one or more of the 23 paired chromosomes. Results from failure of chromosome 21 to separate during egg development. Results in a fertilized egg that has 3 #21"s.