Allele

Allele Latest News

A study from South Africa finds that while protective HLA-B alleles once aided survival and reduced HIV transmission before Antiretroviral therapy, widespread ART use has significantly slowed this natural selection-driven genetic shift.

About Allele

• An allele is a variant form of a gene. 
• Some genes have a variety of different forms, which are located at the same position, or genetic locus, on a chromosome. 
• Humans are called diploid organisms because they have two alleles at each genetic locus, with one allele inherited from each parent. 
• Each pair of alleles represents the genotype of a specific gene. 
• Genotypes are described as homozygous if there are two identical alleles at a particular locus and as heterozygous if the two alleles differ. 
• Alleles contribute to the organism’s phenotype, which is the outward appearance of the organism. 
• Some alleles are dominant or recessive. When an organism is heterozygous at a specific locus and carries one dominant and one recessive allele, the organism will express the dominant phenotype. 
• This genetic diversity allows offspring to inherit traits from both parents while exhibiting unique characteristics. 
• For example, in hair color, dark hair is typically dominant over light hair; a child may inherit light hair only if both parents pass on the recessive allele. 
• All genetic traits are the result of the interactions of alleles. 
• Mutation, crossing over, and environmental conditions selectively change the frequency of phenotypes (and thus their alleles) within a population.

Source: TH

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