Lecture 4 - Genetic Variation & the Hardy-Weinberg equation Flashcards
What is genetic variation?
It is differences among individuals in the composition of their genes or DNA sequences, however, it does not always lead to phenotypic differences.
Why don’t all phenotypic differences indicate genetic variation?
Due to phenotypic plasticity
What are 3 sources of genetic variation?
- Point mutations
- Chromosomal mutations
- Crossing over during meiosis
What is neutral varitaion?
It is a genetic variation that does not provide a selective advantage or disadvantage.
What type of cells must point and chromosomal mutations occur in?
They must occur in gametes and not somatic cells to be heritable.
What is a dominant allele?
It is the allele that determines the phenotype. However, it is not always the most common or adaptive allele.
What is a population?
A group of individuals of the same species that live in the same area and interbreed, leaving viable offspring.
What is a gene pool?
It is all copies of all alleles at every locus in all members of the population.
What is the Hardy-Weinberg principle?
If alleles are transmitted by meiosis and random mating, the gene frequencies of a population will NOT change over time.
What are the 5 assumptions of Hardy-Weinberg equilibrium?
- Random mating
- Large population
- No mutation
- No natural selection
- No gene flow
Why is Hardy-Weinberg a null hypothesis?
It shows the frequencies of alleles and genotypes in the absences of evolution.
