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_L6VY93	Balaena mysticetus	PDHA2	LOF (frameshift, premature stop, ss)	Full	Cetacea	10.1016/j.cub.2021.05.062
GL_LMPN4H	Monodon monoceros	GAPDHS	LOF (frameshift, premature stop, ss)	Full	Monodontidae	10.1016/j.cub.2021.05.062
GL_M2YD7X	Balaenoptera physalus	ALDOA	LOF (frameshift, premature stop, ss)	Full	Cetacea	10.1016/j.cub.2021.05.062
GL_MCO9A2	Lipotes vexillifer	PGK2	Gene deletion	Full	Lipotidae	10.1016/j.cub.2021.05.062
GL_MJ9QE6	Sousa chinensis	LDHC	Exon(s) deletion	Full	Delphinidae	10.1016/j.cub.2021.05.062
GL_ML7FCM	Neophocaena asiaeorientalis asiaeorientalis	GAPDHS	LOF (frameshift, premature stop, ss)	Full	Phocoenidae	10.1016/j.cub.2021.05.062
GL_MVC9NG	Balaena mysticetus	OXCT2	Exon(s) deletion	Full	Cetacea	10.1016/j.cub.2021.05.062
GL_NVZQNH	Megaptera novaeangliae	ALDOA	LOF (frameshift, premature stop, ss)	Full	Cetacea	10.1016/j.cub.2021.05.062
GL_O5SFCX	Neophocaena asiaeorientalis asiaeorientalis	MPC1L	LOF (frameshift, premature stop, ss)	Full	Phocoenidae	10.1016/j.cub.2021.05.062
GL_O7KXLW	Mesoplodon bidens	MPC1L	LOF (frameshift, premature stop, ss)	Full	Ziphiidae	10.1016/j.cub.2021.05.062