Origin of a gene regulatory mechanism in the evolution of echinoderms

• Published in: Nature (London) 1984-07, Vol.310 (5975), p.312-314
• Main Authors: Raff, Rudolf A., Anstrom, John A., Huffman, Carolyn J., Leaf, David S., Loo, Jun-Hun, Showman, Richard M., Wells, Dan E.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Biological Evolution; Cell Nucleus - metabolism; Echinodermata - embryology; Echinodermata - genetics; Echinoidea; Female; Fertilization; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation; Genetics of eukaryotes. Biological and molecular evolution; Histones - genetics; Humanities and Social Sciences; letter; Marine; multidisciplinary; Oogenesis; Ovum - metabolism; Protein Biosynthesis; RNA, Messenger - metabolism; Science; Science (multidisciplinary); Sea Urchins - genetics; Starfish - genetics; Temnopleuridae
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/310312a0

A rich diversity of ancient sea urchin lineages survives to the present. These include several advanced orders as well as the cidaroids, which represent the group ancestral to all other sea urchins. Here we show that all advanced groups of sea urchins examined possess in their eggs a class of maternal messenger RNA (mRNA) encoded by the evolutionary highly conserved α -subtype histone genes. The maternal histone mRNAs are unique in their time of accumulation in oogenesis, their localization in the egg nucleus and their delayed timing of translation after fertilization. Cidaroid sea urchins as well as other echinoderm classes, such as starfish and sea cucumbers, possess the genes but do not have maternal α -subtype histone mRNAs in their eggs. Thus, although all the echinoderms examined transcribe α -subtype histone genes during embryogenesis, the expression of these genes as maternal mRNAs is confined to advanced sea urchins. The fossil record allows us to pinpoint the evolution of this mode of expression of α -histone genes to the time of the splitting of advanced sea urchin lineages from the ancestral cidaroids in a radiation which occurred in a relatively brief interval of time ∼190–200 Myr ago. The origin of a unique gene regulatory mechanism can thus be correlated with a set of macroevolutionary events.