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DTSTAMP:20260312T171913Z
UID:1758533400@ist.ac.at
DTSTART:20250922T113000
DTEND:20250922T123000
DESCRIPTION:Speaker: Ian Henderson\nhosted by Xiaoqi Feng\nAbstract: Abstra
 ct:Centromeres are critical for cell division\, loading CENH3/CENPA histon
 e variant nucleosomes\, directing kinetochore formation and allowing chrom
 osome segregation. Despite their conserved function\, centromere size and 
 structure are diverse across species. To understand this centromere parado
 x\, it is necessary to know how their diversity is generated\, and whether
  it reflects ancient trans-species variation\, or instead\, rapid post-spe
 ciation divergence. To address these questions\, we have analysed 346 cent
 romeres from 66 Arabidopsis thaliana and two A. lyrata accessions\, which 
 revealed extreme intra- and inter-species diversity. Arabidopsis thaliana 
 centromere repeat arrays are embedded in linkage blocks\, despite ongoing 
 internal satellite turnover\, demonstrating a role for unidirectional gene
  conversion in sequence diversification\, rather than interhomolog unequal
  crossover. Additionally\, centrophilic ATHILA transposons have recently i
 nvaded the satellite arrays. To counter ATHILA invasion\, chromosome-speci
 fic bursts of satellite homogenization generate higher-order repeats and p
 urge transposons\, consistent with cycles of repeat evolution. Centromeric
  sequence changes are even more extreme in comparison between A. thaliana 
 and A. lyrata. Together\, our findings reveal rapid cycles of transposon i
 nvasion and purging via satellite homogenization\, which drive centromere 
 evolution and ultimately contribute to speciation. Most recently\, we have
  extended analysis to a subset of complete genomes generated by the Darwin
  Tree of Life project\, from across Eukaryotes. I will present initial con
 clusions derived from this analysis\, and how far the paradigm from Arabid
 opsis extends across the entire Eukaryotic radiation.Key publications:Wlod
 zimierez\, P.\, Rabanal\, F.\, Burns\, R.\, Naish\, M.\, Primetis\, E.\, S
 cott\, A.\, Mandakova\, T.\, Gorringe\, N.\, Tock\, A.J.\, Holland\, D.\, 
 Fritschi\, K.\, Habring\, A.\, Lanz\, C.\, Patel\, C.\, Schlegel\, T.\, Co
 llenberg\, M.\, Mielke\, M.\, Nordborg\, M.\, Roux\, F.\, Shirsekar\, G.\,
  Alonso-Blanco\, C.\, Lysak\, M.A.\, Novikova\, P.\, Bousios\, A.W.\, Weig
 el\, D.W. and Henderson\, I.R. (2023) Cycles of satellite and retrotranspo
 son evolution in Arabidopsis centromeres. Nature doi:10.1038/s41586-023-06
 062-zNaish\, M.\, Alonge\, M.\, Wlodzimierez\, P.\, Tock\, A.\, Abramson\,
  B.\, Schmucker\, A.\, Mandakova\, T.\, Bhagyshree\, J.\, Lambing\, C.\, K
 uo\, P.\, Yelina\, N.\, Hartwick\, N.\, Colt\, K.\, Smith. L.\, Ton\, J.\,
  Kakutani\, K.\, Martienssen\, R.\, Schneeberger\, K.\, Lysak\, M.\, Berge
 r\, F.\, Bousios\, A.\, Michael\, T.\, Schatz\, M. and Henderson\, I.R. (2
 021) The genetic and epigenetic landscape of the Arabidopsis centromeres. 
 Science eabi7489 (116)Biography:Ian is Professor of Genetics and Epigenetu
 cs in the Department of Plant Sciences at the University of Cambridge. Sin
 ce 2008\, his group has investigated genetic and epigenetic inheritance in
  plants\, with a focus on meiosis. Recently\, his group have used long-rea
 d DNA sequencing to analyse repetitive regions of the genome\, including t
 he centromeres. Their current work includes exploring the roles of recombi
 nation within the centromeres\, and understanding their rapid evolution. W
 ork in the Henderson group also seeks to translate knowledge of recombinat
 ion mechanisms in crop breeding\, to accelerate strain improvement and hel
 p adapt to the changing climate. Prior to arriving in Cambridge\, Ian perf
 ormed post-doctoral research with Prof. Steve Jacobsen (UCLA\, USA) on RNA
 -directed in DNA methylation in plants\, and completed his Ph.D with Prof.
  Dame Caroline Dean (John Innes Centre\, UK) where he investigated control
  of flowering-time by RNA binding proteins. He was elected a member of EMB
 O in 2022.
LOCATION:Raiffeisen Lecture Hall\, ISTA
ORGANIZER:diana.gruber@ista.ac.at
SUMMARY:Ian Henderson: Cycles of centromere evolution in eukaryotes
URL:https://talks-calendar.ista.ac.at/events/5768
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