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A relationship between the alleles of a gene in which one allele produces an effect on phenotype that overpowers or "masks" the contribution of another allele at the same locus; the first allele and its associated phenotypic trait are said to be dominant, and the second allele and its associated trait are said to be recessive. Often, the ...
An allele [1] (or allelomorph) is a variant of the sequence of nucleotides at a particular location, or locus, on a DNA molecule. [2]Alleles can differ at a single position through single nucleotide polymorphisms (SNP), [3] but they can also have insertions and deletions of up to several thousand base pairs.
A multilocus genotype is the combination of alleles found at two or more loci in a single individual. For example, in a diploid species, if there are two SNP loci and the first locus has alleles A and G, while the second locus has alleles T and C, the multilocus genotype can be represented as {A/G,T/C}. If the genome is not haploid then the ...
Alleles at a locus may be dominant or recessive; dominant alleles give rise to their corresponding phenotypes when paired with any other allele for the same trait, whereas recessive alleles give rise to their corresponding phenotype only when paired with another copy of the same allele. If you know the genotypes of the organisms, you can ...
Mendelian traits behave according to the model of monogenic or simple gene inheritance in which one gene corresponds to one trait. Discrete traits (as opposed to continuously varying traits such as height) with simple Mendelian inheritance patterns are relatively rare in nature, and many of the clearest examples in humans cause disorders ...
Purging of deleterious alleles can be achieved on the population genetics level, with as little as a single point mutation being the unit of selection. In such a case, carriers of the harmful point mutation have fewer offspring each generation, reducing the frequency of the mutation in the gene pool.
A particularly important component of the genetic variance is the additive variance, Var(A), which is the variance due to the average effects (additive effects) of the alleles. Since each parent passes a single allele per locus to each offspring, parent-offspring resemblance depends upon the average effect of single alleles. Additive variance ...
The specific case of heterozygote advantage due to a single locus is known as overdominance. [ 2 ] [ 3 ] Overdominance is a rare [ 4 ] condition in genetics where the phenotype of the heterozygote lies outside of the phenotypical range of both homozygote parents, and heterozygous individuals have a higher fitness than homozygous individuals.