Ba. Houlden et al., LOW GENETIC-VARIABILITY OF THE KOALA PHASCOLARCTOS-CINEREUS IN SOUTH-EASTERN AUSTRALIA FOLLOWING A SEVERE POPULATION BOTTLENECK, Molecular ecology, 5(2), 1996, pp. 269-281
Genotyping of koalas at CA-repeat microsatellite loci has revealed sig
nificant differences in the levels of allelic diversity (A) and expect
ed heterozygosity ((H) over bar(E)) between populations from north-eas
tern and south-eastern Australia. In the 10 populations studied, allel
ic diversity ranged from 8.0 in the Nowendoc population to 1.7 in the
Kangaroo Is. population, and values of (H) over bar(E) ranged from 0.8
31 in the Nowendoc population to 0.331 in the Kangaroo Is. population.
Data from pooled populations revealed koalas from the northeastern re
gion had significantly higher levels of allelic diversity (A = 11.5+/-
1.4) than those from south-eastern Australia (A = 5.3+/-1.0). Furtherm
ore significantly higher heterozygosity levels were found in the north
-eastern ((H) over bar(E) = 0.851) vs. the south-eastern ((H) over bar
(E) = 0.436) regions of Australia. Following a near-extinction bottlen
eck in the 1920s, mainland Victorian and Kangaroo Is. koalas have been
involved in an extensive program of relocations. The source populatio
ns of the relocated animals were islands in Westernport Bay, which wer
e founded by very few individuals in the late 1800s and early 1900s. T
he significantly lower levels of variation between south-eastern Austr
alian populations suggests that human intervention has had a severe ef
fect on levels of genetic diversity in this region, and this may have
long-term genetic consequences.