Table of Contents
Which causes genetic variation and can result in different alleles?
Genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism’s offspring).
What are the two main causes of genetic variation?
Natural selection acts upon two major sources of genetic variation: mutations and recombination of genes through sexual reproduction.
What can cause allele frequencies to change in populations?
Natural selection, genetic drift, and gene flow are the mechanisms that cause changes in allele frequencies over time.
What is one cause for the differences in our genes?
Causes of differences between individuals include independent assortment, the exchange of genes (crossing over and recombination) during reproduction (through meiosis) and various mutational events. There are at least three reasons why genetic variation exists between populations.
How does meiosis cause genetic variation?
During meiosis, homologous chromosomes (1 from each parent) pair along their lengths. The chromosomes cross over at points called chiasma. At each chiasma, the chromosomes break and rejoin, trading some of their genes. This recombination results in genetic variation.
What are three sources of genetic variation in a population?
There are three sources of genetic variation: mutation, gene flow, and sexual reproduction. A mutation is simply a change in the DNA. Mutations themselves are not very common and are usually harmful to a population. Because of this, mutations are usually selected against through evolutionary processes.
What are the three main causes of genetic variation?
Overall, the main sources of genetic variation are the formation of new alleles, the altering of gene number or position, rapid reproduction, and sexual reproduction.
What causes allele frequencies to decrease?
Genetic drift can result in the loss of rare alleles, and can decrease the size of the gene pool. Genetic drift can also cause a new population to be genetically distinct from its original population, which has led to the hypothesis that genetic drift plays a role in the evolution of new species.