| 1. |
- Lifjeld, Jan T., et al.
(författare)
-
Rapid sperm length divergence in a polygynandrous passerine: a mechanism of cryptic speciation?
- 2023
-
Ingår i: Evolution; international journal of organic evolution. - 1558-5646. ; 77:11, s. 2352-2364
-
Tidskriftsartikel (refereegranskat)abstract
- When populations become geographically isolated, they begin to diverge in various traits and at variable rates. The dynamics of such trait divergences are relevant for understanding evolutionary processes such as local adaptation and speciation. Here we examine divergences in sperm and body structures in a polygynandrous songbird, the alpine accentor (Prunella collaris) between two allopatric high-altitude populations, in Morocco and Spain. The populations diverged around 82,000 years ago, as estimated with a coalescence-based phylogenetic analysis of genome-wide single-nucleotide polymorphisms. We found that birds in the two areas had nonoverlapping sperm lengths, which suggests adaptation to divergent female reproductive tract environments. Sperm length also showed an exceptionally low coefficient of among-male variation, a signal of strong stabilizing selection imposed by sperm competition. The evolutionary rate of sperm length was almost twice the rates for the most divergent morphological traits and more than three times higher than expected from literature data over a similar generational timescale. This rapid evolution of a key reproductive trait has implications for reproductive isolation and ultimately for speciation. Strong selection for different sperm length optima in allopatry predicts conspecific sperm precedence and disruptive selection in sympatry, hence a possible postcopulatory prezygotic barrier to gene flow.
|
|
| 2. |
- Musilova, Zuzana, et al.
(författare)
-
Vision using multiple distinct rod opsins in deep-sea fishes
- 2019
-
Ingår i: Science. - Washington : American Association of Advanced Science. - 0036-8075 .- 1095-9203. ; 364:6440, s. 588-
-
Tidskriftsartikel (refereegranskat)abstract
- Vertebrate vision is accomplished through light-sensitive photopigments consisting of an opsin protein bound to a chromophore. In dim light, vertebrates generally rely on a single rod opsin [rhodopsin 1 (RH1)] for obtaining visual information. By inspecting 101 fish genomes, we found that three deep-sea teleost lineages have independently expanded their RH1 gene repertoires. Among these, the silver spinyfin (Diretmus argenteus) stands out as having the highest number of visual opsins in vertebrates (two cone opsins and 38 rod opsins). Spinyfins express up to 14 RH1s (including the most blueshifted rod photopigments known), which cover the range of the residual daylight as well as the bioluminescence spectrum present in the deep sea. Our findings present molecular and functional evidence for the recurrent evolution of multiple rod opsin-based vision in vertebrates.
|
|
| 3. |
- Yu, Lei, et al.
(författare)
-
Ocean current patterns drive the worldwide colonization of eelgrass (Zostera marina)
- 2023
-
Ingår i: Nature Plants. - 2055-026X .- 2055-0278. ; 9:8, s. 1207-1220
-
Tidskriftsartikel (refereegranskat)abstract
- Currents are unique drivers of oceanic phylogeography and thus determine the distribution of marine coastal species, along with past glaciations and sea-level changes. Here we reconstruct the worldwide colonization history of eelgrass (Zostera marina L.), the most widely distributed marine flowering plant or seagrass from its origin in the Northwest Pacific, based on nuclear and chloroplast genomes. We identified two divergent Pacific clades with evidence for admixture along the East Pacific coast. Two west-to-east (trans-Pacific) colonization events support the key role of the North Pacific Current. Time-calibrated nuclear and chloroplast phylogenies yielded concordant estimates of the arrival of Z. marina in the Atlantic through the Canadian Arctic, suggesting that eelgrass-based ecosystems, hotspots of biodiversity and carbon sequestration, have only been present there for ~243ky (thousand years). Mediterranean populations were founded ~44kya, while extant distributions along western and eastern Atlantic shores were founded at the end of the Last Glacial Maximum (~19kya), with at least one major refuge being the North Carolina region. The recent colonization and five- to sevenfold lower genomic diversity of the Atlantic compared to the Pacific populations raises concern and opportunity about how Atlantic eelgrass might respond to rapidly warming coastal oceans.
|
|
