A project undertaken at Australian National University, and supervised by Mitzy Pepper
The vast arid zone in Australia is the centrepiece of the continent, and is the largest, and youngest, of Australia’s biomes.
Most of my career has focused on how long-term climatic change and the formation of Australia’s deserts drove the evolution of the spectacular diversity of lizard species living there – a biodiversity phenomenon unmatched anywhere else on earth.
Figure 1.
At the height of the Last Glacial Maximum (LGM) just 18kya, the arid zone was unrecognisable. Cold, windy, largely unvegetated and with active dunefields, any species living there faced a hostile environment that undoubtedly presented a formidable challenge for persistence without significant range shifts and drastic reductions in population size. The genomes of extant organisms record the history of evolutionary and ecological forces that have shaped their populations. Frustratingly however, this very important period in time is so recent that evolutionary processes are not easily reconstructed using standard, easy to collect molecular data.
Whole genomes are the most powerful tool for inferring changes in population size and evolutionary dynamics. Demographic history for an entire population can be inferred from only a single high-quality genome, although there are limits to how recent in the past this can be done reliably (not <100kya). However, analyzing multiple genomes per species enables the precise resolution of recent population size changes, like those during the LGM.
Figure 2.
Through generating gold-standard reference genomes for 3 arid zone lizards, and using the latest methods for demographic inference with genome resequencing for multiple individuals, this proposal aims to tackle a major genetic hurdle for understanding how such a recent and potentially catastrophic time period contributed to generating the gobsmacking diversity of lizards in Australia’s deserts.