Jacquelin, B. | Search bioRxiv

bioRxiv2020

Analysis and annotation of genome-wide DNA methylation patterns in two nonhuman primate species using the Infinium Human Methylation 450K and EPIC BeadChips

The Infinium Human Methylation450 and Methylation EPIC BeadChips are useful tools for the study of the methylation state of hundreds of thousands of CpG across the human genome at affordable cost. However, in a wide range of experimental settings in particular for studies in infectious or brain-related diseases, human samples cannot be easily obtained. Hence, due to their close developmental, immunological and neurological proximity with humans, non-human primates are used in many research fields of human diseases and for preclinical research. Few studies have used DNA methylation microarrays in simian models. Microarrays designed for the analysis of DNA methylation patterns in the human genome could be useful given the genomic proximity between human and nonhuman primates. However, there is currently information lacking about the specificity and usability of each probe for many nonhuman primate species, including rhesus macaques (Macaca mulatta), originating from Asia, and African green monkeys originating from West-Africa (Chlorocebus sabaeus). Rhesus macaques and African green monkeys are among the major nonhuman primate models utilized in biomedical research. Here, we provide a precise evaluation and re-annotation of the probes of the two microarrays for the analysis of genome-wide DNA methylation patterns in these two Cercopithecidae species. We demonstrate that up to 162,000 of the 450K and 255,000 probes of the EPIC BeadChip can be reliably used in Macaca mulatta or Chlorocebus sabaeus. The annotation files are provided in a format compatible with a variety of preprocessing, normalization and analytical pipelines designed for data analysis from 450K/EPIC arrays, facilitating high-throughput DNA methylation analyses in Macaca mulatta and Chlorocebus sabaeus. They provide the opportunity to the research community to focus their analysis only on those probes identified as reliable. The described analytical workflow leaves the choice to the user to balance coverage versus specificity and can also be applied to other Cercopithecidae species.

genomics↗

bioRxiv2016

Ancient hybridization and strong adaptation to viruses across African vervet monkey populations

Vervet monkeys (genus Chlorocebus, also known as African green monkeys), are highly abundant in savannahs and riverine forests throughout sub-Saharan Africa. They are amongst the most widely distributed nonhuman primates, show considerable phenotypic diversity, and have long been an important biomedical model for a variety of human diseases1 and in vaccine research2-4. They are particularly interesting for HIV/AIDS research as they are the most abundant natural hosts of simian immunodeficiency virus (SIV), a close relative of HIV. Here we present the first genome-wide survey of polymorphism in vervets, using sequencing data from 163 individuals sampled from across Africa and the Caribbean islands where vervets were introduced during the colonial era. We find high diversity, within and between taxa, and clear evidence that taxonomic divergence was reticulate rather than following a simple branching pattern. A scan for diversifying selection across vervet taxa yields gene enrichments much stronger than in similar studies on humans5. In particular, we report strong and highly polygenic selection signals affecting viral processes -- in line with recent evidence that proposes a driving role for viruses in protein evolution in mammals6. Furthermore, selection scores are highly elevated in genes whose human orthologs interact with HIV, and in genes that show a response to experimental SIV infection in vervet monkeys but not in rhesus macaques, suggesting that part of the signal reflects taxon-specific adaptation to SIV. Intriguingly, rather than affecting genes with antiviral and inflammatory-related functions7, selection in vervets appears to have primarily targeted genes involved in the transcriptional regulation of viruses, and in particular those that are harmful only under immunodeficiency, suggesting adaptation to living with SIV rather than defense against infection.

evolutionary biology↗