Gavin Kelsey

Research Summary

As well as genetic information, the egg and sperm also contribute epigenetic annotations that may influence gene activity after fertilisation. These annotations may be direct modifications of the DNA bases or of the proteins around which the DNA is wrapped into chromatin. Our goal is to understand whether, through epigenetics, factors such as a mother’s age or diet have consequences on the health of a child.
 
We examine how epigenetic states are set up in oocytes – or egg cells – and influence gene expression in the embryo. For example, repressive chromatin marks in oocytes lead to long-term silencing of genes inherited from the mother, particularly in cells that will form the placenta. We are also interested in how variations in DNA methylation come about in oocytes and whether we can use this variation as a marker for oocyte quality and embryo potential. To investigate these questions, we develop methods to profile epigenetic information in very small numbers of cells or even in single cells.

Latest Publications

The enigma of DNA methylation in the mammalian oocyte.
Demond H, Kelsey G

The mammalian genome experiences profound setting and resetting of epigenetic patterns during the life-course. This is understood best for DNA methylation: the specification of germ cells, gametogenesis, and early embryo development are characterised by phases of widespread erasure and rewriting of methylation. While mitigating against intergenerational transmission of epigenetic information, these processes must also ensure correct genomic imprinting that depends on faithful and long-term memory of gamete-derived methylation states in the next generation. This underscores the importance of understanding the mechanisms of methylation programming in the germline. methylation in the oocyte is of particular interest because of its intimate association with transcription, which results in a bimodal methylome unique amongst mammalian cells. Moreover, this methylation landscape is entirely set up in a non-dividing cell, making the oocyte a fascinating model system in which to explore mechanistic determinants of methylation. Here, we summarise current knowledge on the oocyte DNA methylome and how it is established, focussing on recent insights from knockout models in the mouse that explore the interplay between methylation and chromatin states. We also highlight some remaining paradoxes and enigmas, in particular the involvement of non-nuclear factors for correct methylation.

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F1000Research, 9, 1, 2020

DOI: 10.12688/f1000research.21513.1

PMID: 32148772

Correction to: Genome-wide assessment of DNA methylation in mouse oocytes reveals effects associated with in vitro growth, superovulation, and sexual maturity.
Saenz-de-Juano MD, Ivanova E, Billooye K, Herta AC, Smitz J, Kelsey G, Anckaert E

After publication of the original article [1], we were notified that the software used to create the figures has exported them wrong so they display incomplete

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Clinical epigenetics, 12, 1, 27 Jan 2020

DOI: 10.1186/s13148-020-0812-0

PMID: 31987054

The genetic landscape of Arab Population, Chechens and Circassians subpopulations from Jordan through HV1 and HV2 regions of mtDNA.
Al-Eitan L, Saadeh H, Alnaamneh A, Darabseh S, Al-Sarhan N, Alzihlif M, Hakooz N, Ivanova E, Kelsey G, Dajani R

Mitochondrial DNA (mtDNA) is widely used in several fields including medical genetics, forensic science, genetic genealogy, and evolutionary anthropology. In this study, mtDNA haplotype diversity was determined for 293 unrelated subjects from Jordanian population (Circassians, Chechens, and the original inhabitants of Jordan). A total of 102 haplotypes were identified and analyzed among the populations to describe the maternal lineage landscape. Our results revealed that the distribution of mtDNA haplotype frequencies among the three populations showed disparity and significant differences when compared to each other. We also constructed mitochondrial haplotype classification trees for the three populations to determine the phylogenetic relationship of mtDNA haplotype variants, and we observed clear differences in the distribution of maternal genetic ancestries, especially between Arab and the minority ethnic populations. To our knowledge, this study is the first, to date, to characterize mitochondrial haplotypes and haplotype distributions in a population-based sample from the Jordanian population. It provides a powerful reference for future studies investigating the contribution of mtDNA variation to human health and disease and studying population history and evolution by comparing the mtDNA haplotypes to other populations.

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Gene, 729, 1, 01 Mar 2020

DOI: 10.1016/j.gene.2019.144314

PMID: 31884104