Recessive

Recessive refers to the attribute of a gene or allele that is not expressed when paired with a dominant allele. The traits associated with recessive genes only manifest when an organism has two copies of the recessive allele, typically one from each parent. This is a fundamental concept in the study of genetics and heredity.

Overview

In the context of genetics, recessive refers to the characteristic of an allele that does not express its effect in the presence of a dominant allele. This means that the trait associated with the recessive allele will only be visible in the phenotype of an organism if the organism has two copies of the recessive allele. This is often represented in Punnett squares, a diagram used in the study of heredity.

Recessive Traits

Recessive traits are those that are expressed only when an organism has two copies of the recessive allele. These traits can be passed down through generations without being expressed, only to appear when two carriers of the recessive allele reproduce. Examples of recessive traits in humans include certain forms of color blindness, cystic fibrosis, and sickle cell anemia.

Recessive Diseases

Many genetic diseases are caused by recessive alleles. These diseases can often be traced back through a family tree, as they require both parents to be carriers of the recessive allele. Some of the most common recessive diseases include cystic fibrosis, sickle cell anemia, and Tay-Sachs disease.

See Also

• Dominant (genetics)
• Codominance
• Incomplete dominance
• Mendelian inheritance
• Genotype
• Phenotype

References

Recessive Resources
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