Minor allele frequency (MAF) is the frequency at which the second most common allele occurs in a given population. … Single nucleotide polymorphisms (SNPs) with a minor allele frequency of 0.05 (5%) or greater were targeted by the HapMap project.
What does a low minor allele frequency mean?
If the MAF is low, it might imply that the major allele for the SNP is conserved and more or less fixed, but not necessarily. This measure gives an idea about the variation of genotypes for a given SNP in a given population, in other words it gives an idea about how common that SNP is.
What is considered a rare allele frequency?
Traditionally, rare alleles have been defined in terms of their relative frequencies. For example, Kimura (1983a) defines a rare variant as an allele with a relative frequency of less than q, for some small pre-specified value of q such as 0.01.
What is major allele frequency?
In addition, the major allele, by definition, could have a frequency of 50.5%, in which case, although it is more frequent, it is only more frequent by 0.5%.
Why is minor allele frequency important?
MAF is widely used in population genetics studies because it provides information to differentiate between common and rare variants in the population. … As an example, a 2015 study sequenced the whole genomes of 2,120 Sardinian individuals.
What is the frequency of a dominant allele?
The frequency of the dominant allele in the population. Answer: The frequency of the dominant (normal) allele in the population (p) is simply 1 – 0.02 = 0.98 (or 98%). The percentage of heterozygous individuals (carriers) in the population.
Why is there a 2 in 2pq?
The term p2 represents the frequency of dominant homozygotes (AA) and the term q2 represents the frequency of recessive homozygotes (aa). p represents the allele frequency of allele A, and q represents the allele frequency of the allele a.
What will happen to the frequency of the recessive allele?
The answer is the frequency of the recessive allele will increase.
How do you identify rare variants?
One approach is to test each variant individually using a standard contingency table or regression method. However, this approach has low statistical power to detect an association between the rare variants and the trait owing to their small allele frequencies (14, 15, 16).
What can alleles be?
An allele is a variant form of a gene. … When an organism is heterozygous at a specific locus and carries one dominant and one recessive allele, the organism will express the dominant phenotype. Alleles can also refer to minor DNA sequence variations between alleles that do not necessarily influence the gene’s phenotype.
What is the risk allele?
The term “risk allele” refers to variant(s) with very low penetrance such that their effects are incomplete and do not manifest in a Mendelian pattern of inheritance.
What factors can influence allele frequency?
From the theorem, we can infer factors that cause allele frequencies to change. These factors are the “forces of evolution.” There are four such forces: mutation, gene flow, genetic drift, and natural selection.