Michèle Ramsay

Dr. Michèle Ramsay

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Research Focus & Metrics

Academic Career Length

43Years (1984-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 December 2021 in Nature
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SGSarah E. Graham
Sarah E. Graham
SCShoa L. Clarke
Shoa L. Clarke
KWKuan-Han H. Wu
Kuan-Han H. Wu
Stavroula KanoniStavroula Kanoni
Stavroula Kanoni
GZGreg J. M. Zajac
Greg J. M. Zajac
CWCristen J. Willer
Cristen J. Willer

15 January 2018 in Nature Reviews Genetics
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FCFrancisco Ceballos
Francisco Ceballos
PJPeter Joshi
Peter Joshi
DCDavid W. Clark
David W. Clark
MRMichèle Ramsay
Michèle Ramsay
JWJames F. Wilson
James F. Wilson

3 December 2014 in Nature
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Journal Article
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DGDeepti Gurdasani
Deepti Gurdasani
TCTommy Carstensen
Tommy Carstensen
FAFasil Tekola Ayele
Fasil Tekola Ayele
LPLuca Pagani
Luca Pagani
ITIoanna Tachmazidou
Ioanna Tachmazidou
MSManjinder S. Sandhu
Manjinder S. Sandhu
Given the importance of Africa to studies of human origins and disease susceptibility, detailed characterization of African genetic diversity is needed. The African Genome Variation Project provides a resource with which to design, implement and interpret genomic studies in sub-Saharan Africa and worldwide. The African Genome Variation Project represents dense genotypes from 1,481 individuals and whole-genome sequences from 320 individuals across sub-Saharan Africa. Using this resource, we find novel evidence of complex, regionally distinct hunter-gatherer and Eurasian admixture across sub-Saharan Africa. We identify new loci under selection, including loci related to malaria susceptibility and hypertension. We show that modern imputation panels (sets of reference genotypes from which unobserved or missing genotypes in study sets can be inferred) can identify association signals at highly differentiated loci across populations in sub-Saharan Africa. Using whole-genome sequencing, we demonstrate further improvements in imputation accuracy, strengthening the case for large-scale sequencing efforts of diverse African haplotypes. Finally, we present an efficient genotype array design capturing common genetic variation in Africa.

24 February 2021 in Nature Communications
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PGPuya Gharahkhani
Puya Gharahkhani
EJEric Jorgenson
Eric Jorgenson
PHPirro Hysi
Pirro Hysi
AKAnthony P. Khawaja
Anthony P. Khawaja
SPSarah Pendergrass
Sarah Pendergrass
JWJaney L. Wiggs
Janey L. Wiggs
Primary open-angle glaucoma (POAG), is a heritable common cause of blindness world-wide. To identify risk loci, we conduct a large multi-ethnic meta-analysis of genome-wide association studies on a total of 34,179 cases and 349,321 controls, identifying 44 previously unreported risk loci and confirming 83 loci that were previously known. The majority of loci have broadly consistent effects across European, Asian and African ancestries. Cross-ancestry data improve fine-mapping of causal variants for several loci. Integration of multiple lines of genetic evidence support the functional relevance of the identified POAG risk loci and highlight potential contributions of several genes to POAG pathogenesis, including SVEP1, RERE, VCAM1, ZNF638, CLIC5, SLC2A12, YAP1, MXRA5, and SMAD6. Several drug compounds targeting POAG risk genes may be potential glaucoma therapeutic candidates.

28 October 2020 in Nature
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ACAnanyo Choudhury
Ananyo Choudhury
SAShaun Aron
Shaun Aron
LBLaura R. Botigué
Laura R. Botigué
DSDhriti Sengupta
Dhriti Sengupta
GBGerrit Botha
Gerrit Botha
NHNeil A. Hanchard
Neil A. Hanchard
The African continent is regarded as the cradle of modern humans and African genomes contain more genetic variation than those from any other continent, yet only a fraction of the genetic diversity among African individuals has been surveyed1. Here we performed whole-genome sequencing analyses of 426 individuals—comprising 50 ethnolinguistic groups, including previously unsampled populations—to explore the breadth of genomic diversity across Africa. We uncovered more than 3 million previously undescribed variants, most of which were found among individuals from newly sampled ethnolinguistic groups, as well as 62 previously unreported loci that are under strong selection, which were predominantly found in genes that are involved in viral immunity, DNA repair and metabolism. We observed complex patterns of ancestral admixture and putative-damaging and novel variation, both within and between populations, alongside evidence that Zambia was a likely intermediate site along the routes of expansion of Bantu-speaking populations. Pathogenic variants in genes that are currently characterized as medically relevant were uncommon—but in other genes, variants denoted as ‘likely pathogenic’ in the ClinVar database were commonly observed. Collectively, these findings refine our current understanding of continental migration, identify gene flow and the response to human disease as strong drivers of genome-level population variation, and underscore the scientific imperative for a broader characterization of the genomic diversity of African individuals to understand human ancestry and improve health.

1 November 2015 in Journal of the American Society of Nephrology
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AKAlex N. Kasembeli
Alex N. Kasembeli
RDRaquel Duarte
Raquel Duarte
MRMichèle Ramsay
Michèle Ramsay
PMPulane Mosiane
Pulane Mosiane
CDCaroline Dickens
Caroline Dickens
SNSaraladevi Naicker
Saraladevi Naicker
APOL1 variants are associated with HIV-associated nephropathy and FSGS in African Americans. The prevalence of these variants in African populations with CKD in HIV-1 infection has not been investigated. We determined the role of APOL1 variants in 120 patients with HIV-associated nephropathy and CKD and 108 controls from a South-African black population. Patients with CKD were selected on the basis of histology. Genotypes were successfully determined for APOL1 G1 and G2 variants and 42 single nucleotide polymorphisms, including 18 ancestry informative markers, for 116 patients with CKD (96.7%; 38 patients with HIV-associated nephropathy, 39 patients with HIV-positive CKD, and 39 patients with HIV-negative CKD), and 108 controls (100%). Overall, 79% of patients with HIV-associated nephropathy and 2% of population controls carried two risk alleles. In a recessive model, individuals carrying any combination of two APOL1 risk alleles had 89-fold higher odds (95% confidence interval, 18 to 912; P<0.001) of developing HIV-associated nephropathy compared with HIV-positive controls. Population allele frequencies were 7.3% for G1 and 11.1% for G2. APOL1 risk alleles were not significantly associated with other forms of CKD. These results indicate HIV-positive, antiretroviral therapy–naïve South-African blacks with two APOL1 risk alleles are at very high risk for developing HIV-associated nephropathy. Further studies are required to determine the effect of APOL1 risk variants on kidney diseases in other regions of sub-Saharan Africa.