Biology subjects

Cucina, A.

Publications and source records attributed to Cucina, A..

3 recordsLinked to original sources

bioRxiv2020

A genetic history of the pre-contact Caribbean

Humans settled the Caribbean ~6,000 years ago, with intensified agriculture and ceramic use marking a shift from the Archaic Age to the Ceramic Age ~2,500 years ago. To shed new light on the history of Caribbean people, we report genome-wide data from 184 individuals predating European contact from The Bahamas, Cuba, Hispaniola, Puerto Rico, Curacao, and northwestern Venezuela. A largely homogeneous ceramic-using population most likely originating in northeastern South America and related to present-day Arawak-speaking groups moved throughout the Caribbean at least 1,800 years ago, spreading ancestry that is still detected in parts of the region today. These people eventually almost entirely replaced Archaic-related lineages in Hispaniola but not in northwestern Cuba, where unadmixed Archaic-related ancestry persisted into the last millennium. We document high mobility and inter-island connectivity throughout the Ceramic Age as reflected in relatives buried ~75 kilometers apart in Hispaniola and low genetic differentiation across many Caribbean islands, albeit with subtle population structure distinguishing the Bahamian islands we studied from the rest of the Caribbean and from each other, and long-term population continuity in southeastern coastal Hispaniola differentiating this region from the rest of the island. Ceramic-associated people avoided close kin unions despite limited mate pools reflecting low effective population sizes (2Ne=1000-2000) even at sites on the large Caribbean islands. While census population sizes can be an order of magnitude larger than effective population sizes, pan-Caribbean population size estimates of hundreds of thousands are likely too large. Transitions in pottery styles show no evidence of being driven by waves of migration of new people from mainland South America; instead, they more likely reflect the spread of ideas and people within an interconnected Caribbean world.

genetics↗

bioRxiv2020

Population dynamics in pre-Inca human groups from the Osmore Valley, the Azapa Valley and the coast of the south central Andes

The present study applies a dental morphological perspective to the understanding of the complex population history of pre-contact South-Central Andes, the detection of the underlying dynamics, and the assessment of the biological ties among groups. It takes into account 1665 individuals from 16 sites that date from the Archaic to the Late Intermediate located along the coast, on the altiplano, and in the coastal valleys of both Chile and Peru. The results obtained highlight the need for wider perspectives capable of taking into account both the different micro-regional realities and the region in its ensemble. The population dynamics and mobility patterns detected indicate the widely accepted interpretations and distinctions based on cultural affiliations might be insufficient to comprehend the complex population history of the region, especially because the results obtained in the present study indicate the presence of a general and widespread common morphological background for the inhabitants of some of these cultures (i.e., Moche and Wari) and that the interactions they had throughout time must have been far from inconsequential.

evolutionary biology↗

bioRxiv2017

Comparison of two ancient DNA extraction protocols for skeletal remains from tropical environments

ObjectivesThe tropics harbor a large part of the worlds biodiversity and have a long history of human habitation. However, paleogenomics research in these climates has been constrained so far by poor ancient DNA yields. Here we compare the performance of two DNA extraction methods on ancient samples of teeth and petrous portions excavated from tropical and semitropical sites in Tanzania, Mexico, and Puerto Rico (N=12).\n\nMaterials and MethodsAll samples were extracted twice, built into double-stranded sequencing libraries, and shotgun sequenced on the Illumina HiSeq 2500. The first extraction protocol, Method D, was previously designed for recovery of ultrashort DNA fragments from skeletal remains. The second, Method H, modifies the first by adding an initial EDTA wash and an extended digestion and decalcification step.\n\nResultsNo significant difference was found in overall ancient DNA yields or post-mortem damage patterns recovered from samples extracted with either method, irrespective of tissue type. However, Method H samples had higher endogenous content and more mapped reads after quality-filtering, but also higher clonality. In contrast, samples extracted with Method D had shorter average DNA fragments.\n\nDiscussionBoth methods successfully recovered endogenous ancient DNA. But, since surviving DNA in ancient or historic remains from tropical contexts is extremely fragmented, our results suggest that Method D is the optimal choice for working with samples from warm and humid environments. Additional optimization of extraction conditions and further testing of Method H with different types of samples may allow for improvement of this protocol in the future.

genetics↗