chapter  7
Biological Consequences of Dosage Dependent Gene Regulation in Multicellular Eukaryotes
Pages 17

Recent evidence from a variety o f studies has indicated that gene regulatory mechanisms in multicellular eukaryotes operate in a dosage dependent manner. A consequence o f this fact is that new mutations in regulatory loci are available for adaptive selection in the heterozygous state, which is consistent with previous hypotheses that morphological evolu= tion occurs primarily via regulatory genes. Their dosage dependent nature also suggests a com= mon basis for phenomena that result from changes in chromosomal dosage, such as aneuploid syndromes and dosage compensation. Moreover, many quantitative trait loci have been molecularly defined as regulatory genes that exhibit semi-dominant behavior, suggesting also a common basis in the dosage dependent nature o f regulatory hierarchies.