Population structure in the Australian Brush-turkey
We intend to investigate the genetic population structure (and breeding system) of the Australian Brush-turkey (Alectura lathami) using microsatellite markers.
The Australian Brush-turkey lives in rainforests along the coast and inland on the North East corner of Australia. The descendant of this species were once found in the ancient land mass of Gondwana and their nearest extant relatives are found in Papua New Guinea and South America. Today the species is found from the Cape York Peninsula in the north down to Gosford, New South Wales in the South. The Australian Brush-turkey is threatened by habitat destruction and is now locally extinct in some of its pre-European range. Individuals spend most of their time on the ground but do roost in trees at night.
Genetic Analysis of Population Structure
No published microsatellite markers are available for this species. We have therefore recently created an Australian Brush-turkey microsatellite-enriched genomic library and successfully isolated almost 100 microsatellite sequences. We have designed primer sets from these sequences which we are currently validating. We will select 20 polymorphic loci to investigate of the genetic population structure and the breeding systems of the Australian Brush-turkey. We have 60 individuals collected at 6 sites across the range of the species and intend to investigate the population structure among these individuals.
Males can be distinguished from females by the colour and size of the wattle and their call. Australian Brush-turkeys belong to the Megapodiidae family which is the only bird family that does not use body heat to incubate its eggs (Jones and Goth, 2008). A single male will build an incubation mound of leaf litter and other decomposing organic material in which several females lay about 18-24 eggs (Jones 1988). The incubation temperature leads to biased sex ratios, as is observed in reptiles (Goth & Booth, 2005).
Genetic Analysis of the Breeding System
An early study based on minisatellite loci suggested that the mound-owning male is not the father of all the offspring which have been incubated in his mound (Birks, 1997). We have identfied genetic markers suitable to confidently sex individuals of this species. The microsatellite markers we intend to develop could be utilised to investigate breeding systems of this species. However due to the poor weather during the breeding season (Winter 2010-February 2011) we are still in the process of trying to obtain samples of family groups. If you can help with this please contact Dr Deborah Dawson (D.A.Dawson@Sheffield.ac.uk).
Filipa Martins (Leonardo Da Vinci Scholarship 2011, Faculty of Sciences of the University of Lisbon)
Dr. Gavin Horsburgh
Birks S (1997) Paternity in the Australian brush-turkey, Alectura lathami, a megapode bird with uniparental male care. Behavioural Ecology 8, 560-568
Goth A & Booth DT (2005) Temperature-dependent sex-ratio in a bird. Biology Letters, 1, 31-33.
Jones DN (1998) Construction and maintenance of the incubation mounds of the Australian Brush-turkey Alectura lathami. Emu, 88, 210-218.
Jones DN, Dekker RWRJ and Roselaar CS (1995) The Megapodes. Oxford University Press Inc., New York
Jones DN & Goth A (2008) Mound-builders. Australian Natural History Series, CSIRO Publishing, Melbourne