MangroveDieback
“Unprecedented”
Aninternational wetland conference in Darwin
has been told that the magnitude of dieback of
mangroves in northern Australia is “unprece-
dented and deeply concerning”.
Australia is home to 7% of the world’s
mangroves, which take in 50 times more carbon
than tropical forests by area. “Shoreline stability
and isheries values, amongst other beneits of
mangrove vegetation, are under threat,” Prof
Norm Duke of James Cook University told the
Australian Mangrove and Saltmarsh Network
Conference.
Duke said the phenomenon was especially
alarming in light of the large-scale coral bleaching
of the Great Barrier Reef, as it also appeared to
correlate with this year’s extreme warming and
climate events in the region.
Duke said understanding of the scale of the
mangrove loss is currently hampered by the critical lack of detailed
shoreline monitoring, particularly in remote areas of northern
Australia.
Conference delegates called for mangrove-monitoring efforts to
be scaled-up as a matter of priority so that scientists could estab-
lish baseline conditions of national shorelines, and quickly isolate
and manage dieback events such as those seen across hundreds of
hectares in two locations on the coast of the Gulf of Carpentaria- at Limmin Bight in the Northern Territory and Karumba in
Queensland.
Duke said the next step in the investigation into the Gulf of
Carpentaria dieback would be to start ield investigations to deter-
mine the cause and begin appropriate management measures.
JUNE 2016|| 11Gene variants that increase a woman’s
chance of giving birth to non-identical twins
by 29% have been identiied by researchers
from Queensland, Iceland, The Nether-
lands and the US.
A/Prof Dale Nyholt of the Queensland
University of Technology Institute of
Health and Biomedical Innovation said the
identiication of the two DNA variants
associated with a higher chance of non-
identical twins also shed light on female
fertility by identifying key mechanisms
controlling ovarian function.
“We found one variant is close to the
gene coding for the secretion of the
hormone that stimulates ovarian follicles
to release an egg, and the second variant is
in a location likely to be involved in the
ovaries’ response to follicle-stimulating
hormone,” he said. “When both variants
are present, a woman has a 29% greater
chance of having non-identical twins.”
Nyholt said one of the gene variants also
had signiicant effects on other fertility
measures, including the age of a girl’s irst
period, age at menopause, number of chil-
dren, and the age at irst and last child. “It
also affects the genes behind polycystic ovarysyndrome, which is a major cause of female
infertility,” he said.
“This discovery will help research on the
response to hormone stimulation for
assisted reproduction such as IVF.”
While there are more genes to be found
that inluence non-identical twin birth,
Nyholt said that a simple gene test could
be developed to identify women at risk of
a strong response to hormonal treatment
that could prevent the serious complica-
tion of ovarian hyperstimulation
syndrome.
The research has been published in
the American Journal of Human Genetics
(http://tinyurl.com/jho9vru).Genes Raise Chance of Twins
Barbara Helgason/adobe