dosage compensation

views updated May 18 2018

dosage compensation A genetic process that compensates for genes which exist in two doses in the homozygous dominants, so that the heterozygotes produce the same amount of gene product as the homozygotes. In animals, dosage compensation occurs because of the location of the relevant genes on the X-chromosome. In plants, sex determination may be under direct genetic control or may result from the disposition of appropriate hormones (which are themselves genetically controlled), and in only a few plants (e.g. willow) does sex appear to be determined by two sex chromosomes, as it is in mammals.

dosage compensation

views updated May 18 2018

dosage compensation A genetic process that compensates for genes that exist in two doses in the homogametic sex and one in the heterogametic sex as a result of their location on the X-chromosome. The process is not universal among species. For example, in Drosophila, the heterogametic male has one X-chromosome which doubles its effect, while in humans, in the homogametic female only one of the two X-chromosomes is functional.