Crossing over creates genetic variation by exchanging DNA between two nonsister chromatids to produce genetically unique chromosomes. The process of crossing over occurs during... Crossing over creates genetic variation by exchanging DNA between two nonsister chromatids to produce genetically unique chromosomes.
Insertion or deletion, also known as ‘indel’ Insertion or deletion of a single stretch of DNA sequence that can range from two to hundreds of base-pairs in length (Figure 4). Figure 4 Indels affect a string of base-pairs. In this example the insertion string shows that GTA has been inserted, and the deletion string shows a deletion of CA.
It's useful to think of mutation as a process that creates genetic variation. We often refer to a mutation as a thing—the genetic variation itself. This approach can be useful when it comes to a gene associated with a disease: the disease allele carries a mutation, a DNA change that compromises the protein's function.
A gene mutation is a permanent alteration in the DNA sequence that makes up a gene, such that the sequence differs from what is found in most people. Mutations range in size; they can affect anywhere from a single DNA building block (base pair) to a large segment of a chromosome that includes multiple genes.
Random fertilization means that the collection of genes within one gamete (such as a sperm cell) do not give that gamete a lesser or better chance than any of the other sperm cells of fusing with an egg cell to produce a zygote. This does not really generate new variation within the species, but it does preserve the variation that is already there.
The mating of individuals in a population such that the union of individuals with the trait under study occurs according to the product rule of probability.” random mating definition. Non-random Mating. Basically, random mating maintains the level of genetic variation in a population.
Genetic variation is a result of subtle differences in our DNA. Single nucleotide polymorphisms (SNPs, pronounced ‘snips’) are the most common type of genetic variation amongst people. Each single nucleotide polymorphism represents a difference in a single DNA base, A, C, G or T, in a person’s DNA.
Sub-microscopic structural variation. Sub-microscopic structural variants are much harder to detect owing to their small size. The first study in 2004 that used DNA microarrays could detect tens of genetic loci that exhibited copy number variation, deletions and duplications, greater than 100 kilobases in the human genome.