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_A3U6QS	Pontoporia blainvillei	GAPDHS	LOF (frameshift, premature stop, ss)	Full	Pontoporiidae	10.1016/j.cub.2021.05.062
GL_AGQEKM	Neophocaena asiaeorientalis asiaeorientalis	ALDOA	LOF (frameshift, premature stop, ss)	Full	Cetacea	10.1016/j.cub.2021.05.062
GL_AJPMLQ	Mesoplodon bidens	GAPDHS	LOF (frameshift, premature stop, ss)	Full	No	10.1016/j.cub.2021.05.062
GL_AKB0SL	Tursiops truncatus	PGK2	Gene deletion	Full	Delphinidae	10.1016/j.cub.2021.05.062
GL_AUU5NL	Ziphius cavirostris	PDHA2	LOF (frameshift, premature stop, ss)	Full	Cetacea	10.1016/j.cub.2021.05.062
GL_AZTRX9	Globicephala melas	LDHC	Exon(s) deletion	Full	Delphinidae	10.1016/j.cub.2021.05.062
GL_BDPWGA	Lagenorhynchus obliquidens	ALDOA	LOF (frameshift, premature stop, ss)	Full	Cetacea	10.1016/j.cub.2021.05.062
GL_BG5OF8	Heterocephalus glaber	GAPDHS	Exon(s) deletion	Full	Heterocephalus	10.1016/j.cub.2021.05.062
GL_BPX2ZI	Monodon monoceros	PGK2	Gene deletion	Full	Monodontidae	10.1016/j.cub.2021.05.062
GL_BWXIT5	Tursiops truncatus	LDHC	Exon(s) deletion	Full	Delphinidae	10.1016/j.cub.2021.05.062