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 3 causes of genetic variation?
For a given population, there are three sources of variation: mutation, recombination, and immigration of genes. However, recombination by itself does not produce variation unless alleles are segregating already at different loci; otherwise there is nothing to recombine.
What causes the most genetic variation?
Mutations, the changes in the sequences of genes in DNA, are one source of genetic variation. Another source is gene flow, or the movement of genes between different groups of organisms. Finally, genetic variation can be a result of sexual reproduction, which leads to the creation of new combinations of genes.
What happens if you have 50 chromosomes?
These findings show that initial hyperdiploidy (greater than 50 chromosomes) is an independent favorable prognostic sign in childhood ALL and additional chromosomal structural abnormalities may not indicate a poor prognosis among childhood ALL with hyperdiploidy (greater than 50 chromosomes).
How do you identify genetic variation?
Genetic variation refers to diversity in gene frequencies. Genetic variation can refer to differences between individuals or to differences between populations. Mutation is the ultimate source of genetic variation, but mechanisms such as sexual reproduction and genetic drift contribute to it as well.
What are 2 main sources of genetic variation?
Natural selection acts upon two major sources of genetic variation: mutations and recombination of genes through sexual reproduction.
What is an example of variation?
For example, dogs have tails and humans do not. … For example, humans have different coloured eyes, and dogs have different length tails. This means that no two members of a species are identical. The differences between the individuals in a species is called variation.