Research:

We are studying genome structure, ectopic and homologous horizontal gene transfer, stress resistance, and aging in rotifers of Class Bdelloidea.

Bdelloid rotifers are small freshwater invertebrate animals remarkable for their ability to survive desiccation at any life stage, for their lack of males and meiosis, and for their extraordinary resistance to ionizing radiation (IR). Reproduction is from eggs produced by two mitotic divisions from a fixed number of primary oocytes, with no reduction of chromosome number. Lacking meiosis and sexual reproduction, bdelloids nevertheless do engage in homologous horizontal gene transfer within bdelloid species (or clades). We are testing the possibility that such transfer occurs via uptake and integration of DNA released from closely-related bdelloids, analogous to bacterial transformation.

A number of bdelloid characteristics make bdelloids a promising model system for investigating the biology of aging, the time-dependent increase of death rate with age. About two days after hatching, the bdelloids with which we work start to deposit eggs and there is very little mortality until egg deposition is completed, about 12 days after hatching. When egg deposition is completed, however, mortality begins and the death rate increases exponentially with time, doubling every ca. 4 days until the population has expired.

The extraordinary radiation resistance of bdelloids is associated with extremely great protection against oxidative damage, such as the carbonylation of proteins. We are attempting to isolate and characterize the molecular species responsible for such protection. By monitoring IR-induced protein carbonylation and other indicators of oxidative damage before and at various times after the onset of bdelloid aging, and in other experiments as well, we are attempting to critically test the widely-held but unproven hypothesis that oxidative damage is a principal driver of aging.

Making use of the soon to be completed and annotated whole genome sequence of the bdelloid Adineta vaga, and of high throughput sequencing facilities for transcript profiling, we plan to examine the bdelloid transcriptome at intervals before and after the onset of bdelloid aging in order to determine what changes accompany its abrupt onset and acceleration and to identify directions for further research.

We welcome qualified newcomers to our laboratory.

Matthew Meselson is a member of the Mobile Genetic Element Cluster

Recent publications:

Van Doninck, K., M. Mandigo, J. Hur , P. Wang , J. Guglielmini , M. Milinkovitch , W. Lane, M Meselson. (2009). Phylogenomics of Unusual Histone H2A Variants in Bdelloid Rotifers. PLoS Genetics, 5(3): e1000401.

Hur, J., K. Van Doninck, M. Mandigo, M Meselson. (2009). Degenerate Tetraploidy Was Established Before Bdelloid Rotifer Families Diverged. Molecular Biology and Evolution 26:375-383.

Mark Welch D.B, , J.L. Mark Welch, J.L., and M. Melselson. (2008) Evidence for degenerate tetraploidy in bdelloid rotifers. Proc Nat Acad Sci USA 105: 5145-5149.

Gladyshev, E., Meselson, M., 2008. Extreme resistance of bdelloid rotifers to ionizing radiation Proceedings of the National Academy of Sciences 10.1073/pnas.0800966105

Mark Welch D.B., M.P.Cummings, D.M Hillis and M. Meselson (2004). Divergent gene copies in the asexual class Bdelloidea (Rotifera) separated before the bdelloid radiation or within bdelloid families. Proc Natl Acad Sci U S A. 101 : 1622-1625.

Mark Welch J.L., D.B. Mark Welch and M.Meselson (2004). Cytogenetic evidence for asexual evolution of bdelloid rotifers. Proc Natl Acad Sci U S A. 101 : 1618-1621.

Meselson M. (2003). Interview with Matthew Meselson. Bioessays 12 : 1236-46.

Mark Welch D.B. and M. Meselson (2003) Oocyte nuclear DNA content and GC proportion in rotifers of the anciently asexsual Class Bdelloidea. Biological Journal of the Linnean Society 79 : 85-91.

Arkhipova, I.R., K.I. Pyatkov, M. Meselson and M.B. Evgen'ev (2003). Retroelements containing introns in diverse invertebrate taxa. Nature Genetics 33: 123-124.