Gene Loss

Publication Details

Identifier: JB_Z3RO9P

Curator: M. Lopes-Marques

Title:

Complete Inactivation of Sebum-Producing Genes Parallels the Loss of Sebaceous Glands in Cetacea.

Abstract:

Genomes are dynamic biological units, with processes of gene duplication and loss triggering evolutionary novelty. The mammalian skin provides a remarkable case study on the occurrence of adaptive morphological innovations. Skin sebaceous glands (SGs), for instance, emerged in the ancestor of mammals serving pivotal roles, such as lubrication, waterproofing, immunity, and thermoregulation, through the secretion of sebum, a complex mixture of various neutral lipids such as triacylglycerol, free fatty acids, wax esters, cholesterol, and squalene. Remarkably, SGs are absent in a few mammalian lineages, including the iconic Cetacea. We investigated the evolution of the key molecular components responsible for skin sebum production: Dgat2l6, Awat1, Awat2, Elovl3, Mogat3, and Fabp9. We show that all analyzed genes have been rendered nonfunctional in Cetacea species (toothed and baleen whales). Transcriptomic analysis, including a novel skin transcriptome from blue whale, supports gene inactivation. The conserved mutational pattern found in most analyzed genes, indicates that pseudogenization events took place prior to the diversification of modern Cetacea lineages. Genome and skin transcriptome analysis of the common hippopotamus highlighted the convergent loss of a subset of sebum-producing genes, notably Awat1 and Mogat3. Partial loss profiles were also detected in non-Cetacea aquatic mammals, such as the Florida manatee, and in terrestrial mammals displaying specialized skin phenotypes such as the African elephant, white rhinoceros and pig. Our findings reveal a unique landscape of "gene vestiges" in the Cetacea sebum-producing compartment, with limited gene loss observed in other mammalian lineages: suggestive of specific adaptations or specializations of skin lipids.

Last update:

19-06-2024

Associated Glosses (67 results)

GlossID	Species	Symbol	Gene Loss Mechanism	Loss Type	Lineage Specific	Citation
GL_XBHW4N	Balaena mysticetus	DGAT2L6	LOF (frameshift, premature stop, ss)	Full	Cetacea	10.1093/molbev/msz068
GL_XF9SA1	Eschrichtius robustus	AWAT2	LOF (frameshift, premature stop, ss)	Full	No	10.1093/molbev/msz068
GL_XIQAIH	Delphinapterus leucas	AWAT2	LOF (frameshift, premature stop, ss)	Full	No	10.1093/molbev/msz068
GL_YEOCWZ	Balaenoptera bonaerensis	MOGAT3	LOF (frameshift, premature stop, ss)	Full	Cetacea	10.1093/molbev/msz068
GL_YN1MC3	Eschrichtius robustus	MOGAT3	LOF (frameshift, premature stop, ss)	Full	Cetacea	10.1093/molbev/msz068
GL_YRHB48	Balaenoptera bonaerensis	FABP9	LOF (frameshift, premature stop, ss)	Full	Cetacea	10.1093/molbev/msz068
GL_Z85VN8	Sus scrofa	AWAT2	LOF (frameshift, premature stop, ss)	Full	No	10.1093/molbev/msz068