Imprinting

Imprinting is a biological phenomenon that involves the rapid learning process in certain animals shortly after birth or hatching, which establishes a behavior pattern involving recognition of and attraction to a particular type of object. In the context of genetics, genomic imprinting refers to the phenomenon by which certain genes are expressed in a parent-of-origin-specific manner.

Overview

Imprinting is a process that plays a crucial role in the development and behavior of organisms. It is a type of learning that occurs at a particular age or a particular life stage that is rapid and apparently independent of the consequences of behavior. It was first reported in birds, but has since been observed in many species, including humans.

In genetics, genomic imprinting is an epigenetic process that involves methylation and histone modification, resulting in the expression of one allele and not the other. It is an exception to the usual rule of inheritance, which states that both alleles in a heterozygote are functionally equivalent in the offspring.

Biological Imprinting

Biological imprinting is most commonly observed in birds, particularly in species that are precocial (born in an advanced state and able to feed themselves almost immediately). The best-known example is the grey lag goose, which was extensively studied by the Austrian zoologist Konrad Lorenz. Lorenz observed that goslings imprint on the first moving object they see within the first 36 hours after hatching, usually their mother.

Genomic Imprinting

Genomic imprinting is a mechanism by which certain genes are expressed in a parent-of-origin-specific manner. If the allele inherited from the father is imprinted, it is thereby silenced, and only the allele from the mother is expressed. If the allele from the mother is imprinted, then only the allele from the father is expressed.

Imprinted genes are at the heart of a number of genetic diseases and syndromes. For example, Prader-Willi syndrome and Angelman syndrome are caused by a defect in imprinted genes on chromosome 15.

See Also

• Epigenetics
• Genetics
• Konrad Lorenz
• Prader-Willi syndrome
• Angelman syndrome