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A)
Currently in progress: James Rhodes, Masters Degree, Supervised by Dr. C.
Matthee, Stellenbosch University, South Africa
Population
structure of the cape honey badger, Mellivora
capensis based on mtDNA and microsatellite markers (James Rhodes,
Colleen Begg, Keith Begg and Conrad Matthee)
Although
the honey badgers’ distribution is extensive, populations may be
becoming increasingly fragmented. This
is mainly due to conflict between man and nature and habitat
transformation. At present
major conflict exists with honeybadgers and beekeepers and livestock
farmers, and the species is also utilized for traditional medicine. The conservation status of the honey badger is uncertain.
In South Africa, at the recent South African Mammal Conservation
Action Management workshop (CAMP), concern was raised about the decline in
numbers of this species. It
was suggested to classify the animal as near threatened and conservation
dependant.
A
major goal of conservation biology is the preservation of biological
diversity and to maintain the evolutionary patterns and processes that
generated this diversity. It
is therefore crucial to determine intraspecific genetic diversity and
levels of geneflow among populations.
The outcome of such investigations can result in the determination
of conservation units (for example Evolutionary Significant Units or
Management Units). These
units in turn might be restricted to a specific geographic region and also
differ from other such units in other geographic regions.
We
are currently conducting a population genetic study on the African honey
badger.
Several populations throughout the range of the species will be
included. Our aims of this
study are to determine the phylogeographic structure of the honey badger
and to investigate whether there is any genetic evidence to support the
current subspecies taxonomic descriptions. Analyses will be based on
microsatellite and mtDNA control region sequences.
B)
Honours project: Ronelle Verwey, supervised by C. Matthee, Stellenbosch
University, South Africa. Completed. 2002.
Verwey,R.,
Begg,C.M., Begg, K.S. & Matthee, C.A. A microsatellite perspective on
the reproductive success of subordinate male honey badgers, Mellivora
capensis. African Zoology. In press.
A
three-year study of the honey badger in the Kgalagadi Transfrontier
National Park uncovered fundamental information about the breeding system
and social behaviour of the honey badger (Begg 2001, PhD thesis, Mammal
Research Institute, University of Pretoria, South Africa).
It was suggested that the species has a polygynous mating system
(females mate with multiple males), breed throughout the year and cubs are
born following a gestation period of 50 – 70 days.
It was also determined that at any time there are fewer receptive
females than there are males looking for mating opportunities.
Female honey badgers are therefore a scarce resource and as a
result, males move around extensively looking for mating opportunities.
There
seems to be a hierarchy system among male honey badgers which may control
for mating. On several
occasions, subordinate males were observed to gain access to the mating
burrows. The subordinate males, however, only gained access to the females
if the dominant male left the mating burrow to chase off other males or if
the subordinate males arrived at the burrow first. It might thus be
possible that female honey badgers mate with more than one male in a
single receptive period.
Reproductive
behavioural studies can be greatly enhanced by the availability of genetic
markers capable of revealing parentage and other genetic relationships
among individuals. It is not
always possible to obtain relatedness information by simply observing
individuals. The female honey
badger may, for example, mate with several males, but because copulation
is concealed in the burrow, cub paternity is ambiguous.
Microsatellites
are short tandemly repeated DNA sequences dispersed throughout the genome.
For example (ATATATATATATAT).
These repeats form a class of genetic markers that are highly
variable in length due to variability in the number of the repeats (the AT
can be repeated any number of times: for example in the above example the
AT is repeated 7 times). The
alleles are inherited in a simple Mendelian fashion and can thus be used
to reveal parentage. For
example, in most cases of questioned parentage, the mother is known but
the identity of the father is in question. An individual inherits one
allele from each of its parents. Thus,
50% of the individual’s alleles comes from its mother and 50% come from
its father. Comparison of the offspring’s alleles to the suspected
father can therefore exclude (or support) the suspected father as the
biological father. If the
individual has an allele that is absent from both the mother and the
suspected father, the suspected father is not the biological father.
If, however, the individual has an allele that is absent from the
mother but present in the father, the father can not be excluded as the
biological father.
During
the three-year behavioural study by Begg (2001) a total of nine males were
potentially in contact with ten receptive females.
Tissue/hair samples are available for these animals, as well as for
the 10 cubs that resulted from the matings.
The aim of this molecular study is to use microsatellite markers to
assign paternity in the honey badger.
The data obtained allowed us to assess whether the brief mating
opportunities afforded to subordinate males lead to fertilization.
Questions that were addressed are: Did only the dominant male
father cubs? What percentage
of cubs was fathered by subordinate males?
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