Thread by @nancybird_

Excited to share our new paper out in @ScienceAdvances!! We analyse new genetic data from >1300 people from West and Central Africa and Sudan, finding incredible diversity and signals of admixture across the continent. science.org/doi/10.1126/sc…. #ScienceAdvancesResearch thread>

Despite the clear insights into medicine and human history that studying African diversity can provide, African genomes have been, and still are, underrepresented in genetic studies compared to other regions of the world

With our samples we find that genetic structure can correlate with geographic distance, linguistic group, and self-described ethnic group. Some of this structure is seen between groups living <20km apart, and in western Cameroon it might associated with historical polities...

(structure at similarly fine scales has previously been demonstrated in e.g. the UK and Spain, but is often underappreciated in Africa because of sparse sampling)

We then look for signals of admixture. The picture is super complicated, with extensive mixing between geographically disparate groups across the continent at different historical periods. Some of these signals ~might~ be associated with significant events in history

e.g., we can possibly trace the Arabic expansion into Sudan and northern Cameroon. One cool result is that Arabic-like migration and admixture into Sudan is mostly dated after a peace treaty between Makuria (the Kingdom in Sudan at the time) and Arabic groups began to break down

We also infer mixing between northern, western and eastern African-like groups in northern Cameroon during the time of the Kanem-Bornu empire. This was a massive trading empire and might have led to people from all over Africa migrating into the region!!

Finally, we look into the expansion(s?) of Bantu-speaking peoples, potentially one of the largest demographic events in history. We model Cameroonian-like ancestry in Bantu-speaking groups across Africa and favour a 'late split' migration route and potentially multiple waves

We also find intriguing evidence of admixture in southern Cameroon, Nigeria, and Ghana >2000 years ago that we hypothesise might be related to climate change- more genomes needed here!!

This project has made up most of my PhD and it has been so amazing (as a humble geneticist) to work with anthropologists, archaeologists and linguists in Africa and around the world and learn so much history. (pic is me being a tourist in Foumban, Cameroon)

this massive piece of work wouldn’t have been possible without all collaborators. Thanks to all co-authors, including @awahpaschal @Saioa_l @smaceachern2 @mikeweale @DavidZeitlyn @mt_genes @g_hellenthal (as well as those without twitter)