Gene Loss

Publication Details

Identifier: JB_LKCNCT

Curator: Raul Valente

DOI: 10.1016/j.cub.2021.05.062

PMID: 34171300

Title:

A drastic shift in the energetic landscape of toothed whale sperm cells.

Abstract:

Mammalian spermatozoa are a notable example of metabolic compartmentalization.1 Energy in the form of ATP production, vital for motility, capacitation, and fertilization, is subcellularly separated in sperm cells. While glycolysis provides a local, rapid, and low-yielding input of ATP along the flagellum fibrous sheath, oxidative phosphorylation (OXPHOS), far more efficient over a longer time frame, is concentrated in the midpiece mitochondria.2 The relative weight of glycolysis and OXPHOS pathways in sperm function is variable among species and sensitive to oxygen and substrate availability.3-5 Besides partitioning energy production, sperm cell energetics display an additional singularity: the occurrence of sperm-specific gene duplicates and alternative spliced variants, with conserved function but structurally bound to the flagellar fibrous sheath.6,7 The wider selective forces driving the compartmentalization and adaptability of this energy system in mammalian species remain largely unknown, much like the impact of ecosystem resource availability (e.g., carbohydrates, fatty acids, and proteins) and dietary adaptations in reproductive physiology traits.8 Here, we investigated the Cetacea, an iconic group of fully aquatic and carnivorous marine mammals, evolutionarily related to extant terrestrial herbivores.9 In this lineage, episodes of profound trait remodeling have been accompanied by clear genomic signatures.10-14 We show that toothed whales exhibit impaired sperm glycolysis, due to gene and exon erosion, and demonstrate that dolphin spermatozoa motility depends on endogenous fatty acid β-oxidation, but not carbohydrates. Such unique energetic rewiring substantiates the observation of large mitochondria in toothed whale spermatozoa and emphasizes the radical physiological reorganization imposed by the transition to a carbohydrate-depleted marine environment.

Last update:

13-09-2024

Associated Glosses (150 results)

GlossID	Species	Symbol	Gene Loss Mechanism	Loss Type	Lineage Specific	Citation
GL_QQX2AV	Monodon monoceros	LDHC	Exon(s) deletion	Full	Monodontidae	10.1016/j.cub.2021.05.062
GL_R7HUUN	Globicephala melas	PGK2	Gene deletion	Full	Delphinidae	10.1016/j.cub.2021.05.062
GL_RCWQHD	Eubalaena glacialis	PDHA2	LOF (frameshift, premature stop, ss)	Full	Cetacea	10.1016/j.cub.2021.05.062
GL_RH1LMU	Balaenoptera musculus	ALDOA	LOF (frameshift, premature stop, ss)	Full	Cetacea	10.1016/j.cub.2021.05.062
GL_RMTKTB	Phocoena phocoena	GAPDHS	LOF (frameshift, premature stop, ss)	Full	Phocoenidae	10.1016/j.cub.2021.05.062
GL_RSUBEM	Globicephala melas	GK2	LOF (frameshift, premature stop, ss)	Full	Delphinidae	10.1016/j.cub.2021.05.062
GL_S9UJM5	Peponocephala electra	LDHC	Exon(s) deletion	Full	Delphinidae	10.1016/j.cub.2021.05.062
GL_SFSBQK	Neophocaena asiaeorientalis asiaeorientalis	LDHC	LOF (frameshift, premature stop, ss)	Full	Phocoenidae	10.1016/j.cub.2021.05.062
GL_SMJNXB	Peponocephala electra	GAPDHS	LOF (frameshift, premature stop, ss)	Full	Delphinidae	10.1016/j.cub.2021.05.062
GL_SS5TZA	Delphinapterus leucas	GK2	LOF (frameshift, premature stop, ss)	Full	Delphinapterus	10.1016/j.cub.2021.05.062