Gene Loss

Publication Details

Identifier: JB_OVMX0Y

Curator: M. Lopes-Marques

DOI: 10.1016/j.ympev.2017.12.010

PMID: 29277542

Title:

Evolution of the MC5R gene in placental mammals with evidence for its inactivation in multiple lineages that lack sebaceous glands.

Abstract:

MC5R is one of five melanocortin receptor genes found in placental mammals. MC5R plays an important role in energy homeostasis and is also expressed in the terminal differentiation of sebaceous glands. Among placental mammals there are multiple lineages that either lack or have degenerative sebaceous glands including Cetacea (whales, dolphins, and porpoises), Hippopotamidae (hippopotamuses), Sirenia (manatees and dugongs), Proboscidea (elephants), Rhinocerotidae (rhinos), and Heterocephalus glaber (naked mole rat). Given the loss or diminution of sebaceous glands in these taxa, we procured MC5R sequences from publicly available genomes and transcriptomes, supplemented by a newly generated sequence for Choeropsis liberiensis (pygmy hippopotamus), to determine if this gene remains intact or is inactivated in association with loss/reduction of sebaceous glands. Our data set includes complete MC5R sequences for 114 placental mammal species including two individuals of Mammuthus primigenius (woolly mammoth) from Oimyakon and Wrangel Island. Complete loss or inactivation of the MC5R gene occurs in multiple placental lineages that have lost sebaceous glands (Cetacea, West Indian manatee, African elephant, white rhinoceros) or are characterized by unusual skin (pangolins, aardvarks). Both M. primigenius individuals share inactivating mutations with the African elephant even though sebaceous glands have been reported in the former. MC5R remains intact in hippopotamuses and the naked mole rat, although slightly elevated dN/dS ratios in these lineages allow for the possibility that the accumulation of inactivating mutations in MC5R may lag behind the relaxation of purifying selection. For Cetacea and Hippopotamidae, the absence of shared inactivating mutations in two different skin genes (MC5R, PSORS1C2) is consistent with the hypothesis that semi-aquatic lifestyles were acquired independently in these clades following divergence from a common ancestor.

Last update:

20-06-2024

Associated Glosses (17 results)

GlossID	Species	Symbol	Gene Loss Mechanism	Loss Type	Lineage Specific	Citation
GL_MKUEYS	Balaena mysticetus	MC5R	Gene deletion	Full	Cetacea	10.1016/j.ympev.2017.12.010
GL_Q5CIYG	Balaenoptera bonaerensis	MC5R	Gene deletion	Full	Cetacea	10.1016/j.ympev.2017.12.010
GL_QV5MF2	Loxodonta africana	MC5R	LOF (frameshift, premature stop, ss)	Full	No	10.1016/j.ympev.2017.12.010
GL_UEMKCP	Lipotes vexillifer	MC5R	Gene deletion	Full	Cetacea	10.1016/j.ympev.2017.12.010
GL_X1MD1D	Pongo abelii	MC5R	LOF (frameshift, premature stop, ss)	Full	No	10.1016/j.ympev.2017.12.010
GL_XR46X9	Mammuthus primigenius	MC5R	LOF (frameshift, premature stop, ss)	Full	No	10.1016/j.ympev.2017.12.010
GL_YGX7DW	Tursiops truncatus	MC5R	Gene deletion	Full	Cetacea	10.1016/j.ympev.2017.12.010