Dominant allele

Dominant allele is a type of allele that masks the presence of another allele in a heterozygous condition. It is a fundamental concept in the study of genetics, particularly in the fields of genomics and molecular genetics.

Overview

In a pair of alleles, the dominant allele is the one that determines the phenotype, or physical appearance, of an organism. This is in contrast to the recessive allele, which is masked by the dominant allele and only expresses itself when present in a homozygous condition.

Dominance in Genetics

The concept of dominance was first introduced by Gregor Mendel, the father of modern genetics. Mendel's experiments with pea plants led him to the conclusion that certain traits are dominant over others. This discovery formed the basis of Mendel's laws of inheritance, which are still fundamental to the study of genetics today.

Dominant alleles are represented by a capital letter, while recessive alleles are represented by a lowercase letter. For example, in a pair of alleles for flower color, where purple is dominant over white, the dominant allele might be represented as 'P' and the recessive allele as 'p'.

Examples of Dominant Alleles

Examples of traits determined by dominant alleles include:

• Brown eye color: The allele for brown eyes is dominant over the allele for blue eyes.
• Widow's peak: The allele for a widow's peak, a distinctive hairline shape, is dominant over the allele for a straight hairline.
• Tongue rolling: The ability to roll the tongue into a tube shape is determined by a dominant allele.

See Also

• Genotype
• Phenotype
• Homozygous
• Heterozygous
• Gregor Mendel
• Mendelian inheritance

References

Dominant allele Resources
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