Genetic imprinting

Genetic imprinting causes different expressions of the same gene. It is dependent upon which parent the gene is inherited from.

The imprinting itself involves chemical reactions taking place with the DNA that alter not the genes but the expressions of genes (specifically: 'methylation', another term for another day).

Genetic imprinting is the cause for the difference between Prader-Willi syndrome and Angelman syndrome. Both occur due to the same problem (a 'deletion' on chromosome 15), but Prader-Willi is caused by a faulty gene passed down by the father; Angelman from the mother.

Evolutionarily speaking, these diffences occur because of interest differences between the genders.

For example, genetic imprinting is linked with over- and under-expression of genes (think enhancement vs. Suppression). A female (mouse) passing on a suppressed growth-linked gene, and thereby giving birth to smaller young, is more likely to survive and have a high rate of reproduction, while a Male (mouse) 'wants' larger young, so is more likely to be genetically successful if he passes on an enhanced gene.



Saludos Cordiales
Dr. José Manuel Ferrer Guerra