BIO 223 Midterm Flashcards
Frameshift Mutations
- nucleotide pair insertions or deletions
- that alter the reading frame of a gene’s genetic message
- occurs whenever the number of nucleotide pairs that is inserted or deleted is not a multiple of three
- occurs all of the amino acids encoded by the codons after the mutation will be altered
- the protein produced will be abnormal and likely nonfunctional
What is an example of a frameshift mutation?
a single nucleotide pair insertion
What are the three processes in sexually reproducing organisms that lead to the most genetic variation?
- independent assortment of chromosomes in meiosis
- crossing over of chromosomes in meiosis
- random fertilization
Hardy-Weinberg Equilibrium Population
- is a population that is not evolving
- the gene and genotype frequencies remain constant from one generation to the next
Condition for Hardy Weinberg Equilibrium - No Mutations
consequence - the gene pool is modified if mutations occur or if entire genes are deleted or duplicated
Condition for Hardy Weinberg Equilibrium - Random Mating
consequence - if individuals mate within a subset of the population random mixing of gametes does not occur and genotype frequencies change
Ex. as near neighbors or close relatives (inbreeding)
Condition for Hardy Weinberg Equilibrium - No Natural Selection
consequences - allele frequencies change when individuals with different genotypes show consistent difference in their survival or reproductive success
Condition for Hardy Weinberg Equilibrium - Extremely Large Population Size
consequences - (small populations) allele frequencies fluctuate by chance over time
Ex. process called genetic drift
Condition for Hardy Weinberg Equilibrium - No Gene Flow
consequence - by moving alleles into or out of populations (gene flow can alter allele frequencies)
What are the four causes of evolutionary change?
- genetic drift
- gene flow
- mutation
- natural selection
