Our new paper is out in PNAS!
We analyzed 125 high-coverage whole genomes from five Sudanese ethnolinguistic groups, to understand the evolutionary and demographic history of the region.
www.pnas.org/doi/10.1073/...
🧵👇
Posts by Marcos Castro e Silva, PhD 🇧🇷
Excited to share our new preprint🙌
It's the first human WGS study in Sudan. We uncover one of the strongest selection signals to date, pointing to post-admixture adaptation to malaria in Copts. Huge thanks to all co-authors. @aidaandres.bsky.social @jgarcia-cal.bsky.social @ebosch1972.bsky.social
Sudan's complex genetic admixture history drives adaptation to malaria in Sudanese Copts www.medrxiv.org/content/10.1101/2025.09....
A very special paper where we did something NEW! 🔥combining a large genetic dataset 🧬, a large linguistic dataset 💬, and Bayesian multilevel logistic regressions 📈, counting the effects of areal contact (geographic constrains) 🌎. Genetic admixture explains higher levels of linguistic exchanges...
Seeing how every effort has now materialized into lessons and teachings that truly benefit @ibe-barcelona.bsky.social scientists of all generations has been immeasurable. Thank you, @xavimartiperez.bsky.social, for co-leading this project.
Thank you @albanietoh.bsky.social and @xavimartiperez.bsky.social for putting the effort to organizing this workshop! 🙏
Caçadores humanos podem ter sido os principais algozes das preguiças-gigantes. Análises evolutivas indicam que a disseminação de Homo sapiens pela América coincidiu com picos de extinção bit.ly/43dhPTf
#paleontologia #biodiversidade #evolução #zoologia
Obrigado Nikolas!
Huge thanks to the incredible team behind this effort.
Proud to have contributed to the DNA do Brasil project and to shed light on Brazil’s rich genetic history.
🔗 Read the paper: science.org/doi/10.1126/...
🧵Thanks for reading! RTs appreciated. #genomics #Brazil #SciComm
Brazil’s complex genetic history matters—for public health, ancestry, and fairness in precision medicine. Including diverse and admixed populations in genomics isn’t just good science—it’s key to understanding and honoring Brazil’s past.
📉 Genomic data reveals the demographic toll of colonization:
Massive effective population size declines
Regional differences in genetic isolation
Long IBD segments in Amazonas (northern Brazilian state) reveal deep founder effects and recent inbreeding
🧬 We identified ancestry-specific regions under natural selection after admixture:
Genes linked to immune response (MHC/HLA), fertility, metabolism
Selection shaped by regional environments & disease burdens
Especially strong signals from Indigenous ancestry
🌍 Brazilian genomes are a mosaic of haplotypes from Indigenous American, African, and European ancestors.
We uncovered fine-scale structure — some individuals were formed by admixture between African populations that likely never met on the continent itself.
👩🏽🦱🧔🏻♂️ We reconstructed how admixture shaped Brazilian genomes:
Admixture peaked in the 18th–19th centuries
Initially: sex-biased mating (mostly European men + African/Indigenous women)
Now: ancestry-assortative mating dominates
💥 Of these new variants, >36,000 are potentially deleterious — affecting immunity, metabolism, and fertility.
Many are rare and ancestry-specific.
We found correlations between ancestry proportions and deleterious variant burden.
🧬 We generated 2,723 whole-genome sequences (avg. 35x coverage) from across Brazil's 5 regions: including urban, rural, and riverine populations.
This is one of the largest WGS datasets from Latin America.
And we found 8.7 million variants not seen in public datasets.
🇧🇷 Brazil is home to the world’s largest recently admixed population — shaped by millions of Europeans, enslaved Africans, and Indigenous peoples.
Yet, its genomic diversity remains underrepresented in global databases.
We set out to change that.