Hobart

Seminar Abstract

Friday 13 June 2008, 11.30am (Tas time)
CSIRO Auditorium, Hobart

Chris Burridge
Molecular Ecologist Research Scientist
CSIRO Marine and Atmospheric Research, Floreat, WA

Keeping pace with evolution: does younger = faster?

Patterns of DNA variation have provided great insights into studies of ecology and evolution, but knowledge of the rates of DNA change are central to the success of these applications. Previously, pedigree and ancient DNA studies, focusing on evolution in the short term (<100 kyr), have yielded molecular rate estimates substantially faster than those based on phylogenies spanning 'deeper' (>1 Myr) evolutionary time. It has recently been suggested that short-term, elevated molecular rates decay exponentially over 1-2 million years to long-term, 'phylogenetic' rates. This transition has potential to confound molecular inferences of demographic parameters (migration rates, effective population sizes) and dating of many important evolutionary events. We have employed a novel approach, geologically dated changes in river drainages and isolation of fish populations, to document rates of mitochondrial DNA change over a range of temporal scales. This method utilizes precise spatio-temporal disruptions of linear freshwater systems, and hence avoids many of the limitations associated with typical DNA rate calibration methods involving fossil data or island formation.

Studies of freshwater-limited fishes across the South Island of New Zealand have revealed that genetic relationships reflect past, rather than present, drainage connections. Using this link between drainage geology and genetics, we have calibrated rates of molecular evolution across events ranging in age from 0.007 Myr (Holocene) to 5.0 Myr (Pliocene), to address whether the rate of molecular evolution is indeed faster for younger events, and the implications of such a relationship for DNA-based studies.

Christopher P. Burridge (1)*, Dave Craw (2), David Fletcher (3), and Jonathan M. Waters (1)

(1) Department of Zoology, (2) Department of Geology, (3) Department of Mathematics and Statistics, University of Otago, Dunedin, New Zealand

* Present address: CSIRO Marine & Atmospheric Research, Floreat, WA.

[back]

Location:
CSIRO = Marine Laboratories Auditorium, Castray Esplanade, Hobart

For further information, or to schedule a seminar, contact:
To schedule a seminar, contact:
Bernadette Sloyan, (Oceanographic seminars) CSIRO Marine and Atmospheric Research (03) 6232 5152
Thomas Kunz, (Biological seminars) CSIRO Marine and Atmospheric Research
(03) 6232 5076
Natalie Dowling, (Fisheries Modelling) CSIRO Marine and Atmospheric Research
(03) 6232 5148
Jillian Enraght-Moony, (seminar administrator) CSIRO Marine and Atmospheric Research (03) 6232 5320
Communications Manager, Antarctic Climate and Ecosystems CRC (03) 6226 2265
Margaret Hazelwood, Institute of Antarctic and Southern Ocean Studies (IASOS) University of Tasmania (03) 6226 2971

Last updated 21/07/09