Thread by @mitoPR

I am very excited to share our preprint "Ancient DNA reconstructs the genetic legacies of pre-contact Puerto Rico communities”. With contributions by an interdisciplinary team including @StoneLab_ASU @AWRgenes @Conydelafc @DNATimeTravel @cdbustamante 1/n biorxiv.org/content/10.110…

@StoneLab_ASU @AWRgenes @Conydelafc @DNATimeTravel @cdbustamante Here we use aDNA to examine the genetic 🧬diversity of ancient Indigenous communities who inhabited 🇵🇷 before European contact. I want to share my thoughts on why our work is important, both for me personally, and for Caribbean anthropology more broadly 2/n

@StoneLab_ASU @AWRgenes @Conydelafc @DNATimeTravel @cdbustamante The archaeological record tells us that 🇵🇷 & the Caribbean were inhabited by Indigenous ppl for over 5K yrs! But, due to contrasting archaeological evidence the origins of these communities are still disputed 3/n (Image: Fitzpatrick 2015)

@StoneLab_ASU @AWRgenes @Conydelafc @DNATimeTravel @cdbustamante Indigenous Caribbean peoples were also the the first Native American groups to experience European colonization. BC of this our current understanding of the region’s ancient past is fragmented and colored through colonial-tinted glasses 🧐 3/n (Painting by Dióscoro Puebla 1862)

@StoneLab_ASU @AWRgenes @Conydelafc @DNATimeTravel @cdbustamante Many colonial documents say that 🇵🇷's native peoples died out in the 1500s. This led to common narratives of Indigenous extinction, despite the presence of islanders who have oral histories of Indigenous descent and/or Indigenous cultural identities. 4/n

@StoneLab_ASU @AWRgenes @Conydelafc @DNATimeTravel @cdbustamante Both of these are topics have been much debated in Caribbean archaeology and cultural anthropology. Our study intersects and builds upon this previous work by providing a genetic anthropological perspective of pre-contact Puerto Rican history 5/n

@StoneLab_ASU @AWRgenes @Conydelafc @DNATimeTravel @cdbustamante We looked at the DNA of 124 individuals who lived in three sites in PR. This was very challenging bc aDNA is not well preserved in tropical contexts 🏖️🌦️. But using enrichment and NGS we recovered 45 complete mtDNA genomes and 2 partial autosomal genomes 6/n

@StoneLab_ASU @AWRgenes @Conydelafc @DNATimeTravel @cdbustamante With these data, we tested several hypotheses for the peopling of 🇵🇷and the Caribbean and we also examined the question of genetic continuity between ancient populations and present-day islanders 7/n

@StoneLab_ASU @AWRgenes @Conydelafc @DNATimeTravel @cdbustamante Our findings suggest that ancient communities in🇵🇷were related to Amazonian Indigenous peoples. This is consistent with much previous archeological, modern genetics and ethnohistoric research which point to a primarily South American origin for ancient Caribbean communities 8/n

@StoneLab_ASU @AWRgenes @Conydelafc @DNATimeTravel @cdbustamante We also found similar autosomal ancestry patterns between pre-contact individuals from Puerto Rico and one ancient woman from Bahamas, suggesting they both carry a shared component of Indigenous Caribbean ancestry. To read about her go to: pnas.org/content/115/10… 9/n

@StoneLab_ASU @AWRgenes @Conydelafc @DNATimeTravel @cdbustamante Lastly, we show that despite the large-scale population declines that took place in the Caribbean during colonization, some pre-contact genetic diversity survived into the present-day within the genomes of present-day Puerto Ricans 🇵🇷😱✊ 10/n

@StoneLab_ASU @AWRgenes @Conydelafc @DNATimeTravel @cdbustamante More research is still needed to better understand this complex story. Where within the Amazon did these people come from? Did people from other parts of Americas also come to 🇵🇷 but leave no genetic trace? Do other islanders today have similar links? We still don't know! 11/n

@StoneLab_ASU @AWRgenes @Conydelafc @DNATimeTravel @cdbustamante But what is super cool for me is that by using aDNA, and contextualizing our findings with historical, archaeological, biological evidence, we can reconstruct the stories of communities that were marginalized or misrepresented in the documentary historical record 12/n

@StoneLab_ASU @AWRgenes @Conydelafc @DNATimeTravel @cdbustamante As a Puerto Rican 🇵🇷scientist I am honored to study the ancestors of my people and to help tell some of our island's rich history. I even remember visiting some of these sites as a kid! 13/n

@StoneLab_ASU @AWRgenes @Conydelafc @DNATimeTravel @cdbustamante This work was made possible by the help of many, many people and funding from @NSF @ASUBeingHuman and many others. We also stand on the shoulders of giants and couldn't do this research w/o drawing upon yrs of research by others. THANK YOU ALL! 14/14 END (for now...🙃😉)