Genetic diversity Flashcards
What is a gene mutation?
Change to the DNA base sequencce
Why is a deletion mutation more dangerous?
Creates a frameshift so causes all triplet codes after the mutation to change resulting in different amino acids and the protein not being produced
What is polyploidy?
When organisms have three or more sets of each chromosome
What is non-disjunction?
When the individual homologous pairs fail to separate resulting in the gamete having one more or one less chromosomes
Explain why errors in DNA replication can be more damaging than errors to transcription
Error in DNA replication will be passed down to all daughter cells whereas an error in transcription only affects that single mRNA and more can be easily produced
What happens in crossing over?
Chromatids of each pair wrap around each other. This tension causes portions of the chromatids to break off and these broken portions can be rejoined on its homologous partners. This happens at the chiasmata.
What is the difference between anaphase I and anaphase 11?
2- the centromeres break down allowing chromatids to be separated
What is independent segregation?
Homologous chromosomes line up randomly at the equator. the combination of maternal and paternal chromosomes are random.
Which stages of meiosis increase genetic diversity?
Metaphase I- independent segregation
Prophase I- crossing over
What is genetic diversity?
Total number of different alleles in a population
What is allele frequency?
How often a particular allele occurs within a population
What is evolution?
Gradual change of a species characteristics over time due to selection pressures
What is the founder effect?
When a small group of individuals get isolated and have a non-representative sample of alleles compared to the parent population. The allele frequencies will change over time resulting in genetic drift and a difference in characteristics compared to the original population
What is a population bottleneck?
When an unselective event causes a small number of individuals to survive which aren’t representative of the original population which can lead to genetic drift.
What is genetic drift?
When the allele frequencies in a population change overtime
