2025 Hyper Recent •CC0 1.0 Universal

This work is dedicated to the public domain. No rights reserved.

Access Preprint From Server
July 2nd, 2025
Version: 1
Harvard University
evolutionary biology
biorxiv

Avian germline-restricted chromosomes are reservoirs for active long-terminal-repeat retroviruses

Fang, B.Open in Google Scholar•Edwards, S. V.Open in Google Scholar

Germline-restricted chromosomes (GRCs) are unique to germ cells and absent from somatic cells in songbirds. However, their contents, functions, and evolutionary mechanisms remain unclear. We performed comparative genomics on long-read assembled GRCs from male House Finch (Haemorhous mexicanus), Common Rosefinch (Carpodacus erythrinus), and Blue Tit (Cyanistes caeruleus), the first two of which are newly presented and annotated here. These long-read GRCs are repeat-rich (63-74%), despite their wide variation in size (16-160 megabases), individually distinct gene content, and variable evolutionary histories. These GRCs have accumulated intact long terminal repeat (LTR) endogenous retroviruses (ERVs), and their proliferation co-occurs with speciation events of passerine birds. In contrast, normal chromosomes (autosomes and sex chromosomes) are known to purge ERVs through ectopic recombination of LTRs that generate solo LTRs. Furthermore, transcriptomic data reveal significantly higher ERV transcription on GRCs than on A-chrs in House Finch testis. We propose that GRCs act as reservoirs of active ERVs, promoting germline transposition and potentially accelerating adaptation and speciation. This study suggests that GRCs play an indispensable role and likely contribute to adaptive diversification in birds.

Similar Papers

biorxiv
Wed Jul 02 2025
Microbiome evolution plays a secondary role in host rapid adaptation
Understanding how populations adapt to environmental change is a central goal in evolutionary biology. Microbiomes have been proposed as a source of heritable variation that is central to rapid adaptation in hosts, yet empirical evidence supporting this remains limited, particularly in naturalistic settings. We combined a field evolution experiment in Drosophila melanogaster exposed to an insectic...
Shahmohamadloo, R. S.
•
Gabidulin, A. R.
•
Andrews, E. R.
•
Rudman, S. M.
biorxiv
Wed Jul 02 2025
Weak genetic draft and the Lewontin's paradox
Neutral theory assumes that in a population of size N, diversity results from an equilibrium between new mutations arising at rate and genetic drift that purge them at rate 1/N, predicting an equilibrium value proportional to N. The difference between this expectation and the much lower observed molecular diversity is known as Lewontin's paradox of variation. Here, we investigate the effect of ge...
Achaz, G.
•
Schertzer, E.
biorxiv
Wed Jul 02 2025
Cost of altered translation accuracy shapes adaptation to antibiotics in E. coli
Protein synthesis, while central to cellular function, is error-prone. The resulting mistranslation is generally costly, but we do not know how these costs compare or interact with the costs imposed by external selection pressures such as antibiotics. We also do not know whether and how these costs are compensated during evolution. It is important to answer these questions, since mistranslation is...
Samhita, L.
•
Tamhankar, S.
•
Miranda, J.
•
Basu, A. K.
•
Agashe, D.
biorxiv
Wed Jul 02 2025
Dietary Zn governs protein: carbohydrate regulation of fecundity and lifespan in Drosophila melanogaster
Recent work has shown that dietary zinc (Zn) restriction has a strong effect to limit egg production in female Drosophila, while also producing a variable, but beneficial, effect on lifespan. This combination of phenotypes is interesting because it is consistent with the disposable soma theory of ageing, and phenocopies the well-studied effects of reducing the dietary protein-to-carbohydrate (P:C)...
Sarmah, S.
•
Burke, R.
•
Mirth, C.
•
Piper, M.
biorxiv
Wed Jul 02 2025
Synergizing Bayesian and Heuristic Approaches: D-BPP Uncovers Ghost Introgression in Panthera and Thuja
Hybridization involving extinct or unsampled ("ghost") lineages profoundly influences species' evolutionary histories, but detecting such introgression remains methodologically challenging. We introduce D-BPP, a novel framework that integrates the heuristic D-statistic (or ABBA-BABA test) with Bayesian phylogenomic inference (implemented in BPP) to efficiently infer phylogenetic networks. In D-BPP...
Yang, Y.
•
Pang, X.-X.
•
Ding, Y.-M.
•
Zhang, B.-W.
...•
Zhang, D.-Y.
biorxiv
Wed Jul 02 2025
Energetic shifts reflect survival likelihood in Anopheles gambiae
Life history theory predicts that resource allocation adapts to ecological and evolutionary pressures. We investigated resource and energy in the malaria vector Anopheles gambiae following exposure to two stressors: blood meals and infection by the microsporidian Vavraia culicis. Our findings reveal the costs of blood feeding and parasitism on longevity, highlighting trade-offs in lifetime protein...
Zeferino, T. G.
•
Silva, L. M.
•
Koella, J. C.
biorxiv
Wed Jul 02 2025
Phenotypic and transcriptomic similarity between the N2 Ancestral and a Tropical wild isolate of C. elegans reveals divergence from the reference Bristol strain
In recent years, the scientific community has increasingly recognized the importance of incorporating ecologically relevant perspectives into laboratory research. In the case of the free-living nematode Caenorhabditis elegans, numerous studies have documented the domestication of the N2 Bristol strain (isolated in 1951). This has led to a growing interest in recently isolated wild strains from div...
Hersch-Gonzalez, J.
•
Cano-Dominguez, N.
•
Zurita-Leon, M.
•
Soto-Nava, M.
...•
Valdes, J.
biorxiv
Tue Jul 01 2025
Dispersal behavior rather than dispersal morphology creates social polymorphism in Formica ants
Dispersal evolution and social evolution are interlinked. Dispersal is necessary for avoiding kin competition and inbreeding, but limited dispersal also allows beneficial social interactions with kin. In ants, a correlation between poor dispersal and complex societies, where a big proportion of queens are philopatric, is well documented, but the underlying causal mechanisms are not clear. In this ...
Hakala, S. M.
•
Belevich, I.
•
Jokitalo, E.
•
Seppa, P.
•
Helantera, H.
biorxiv
Tue Jul 01 2025
Back-projection improves inference from sparsely sampled genomic surveillance data
Highly transmissible SARS-CoV-2 variants have emerged throughout the COVID-19 pandemic, driving new waves of infections. Genomic surveillance data can provide insights into the virus\'s evolution and biology. However, delayed and limited regional data can introduce biases in epidemiological models, potentially obscuring transmission patterns. To address this issue, we used a novel, variant-specifi...
Finney, E. E.
•
Lee, B.
•
Ahmed, S. F.
•
Sohail, M. S.
...•
Barton, J. P.