Genetics: Setting the biological clock


A series of studies has tracked possible genetic influences on when a woman's reproductive lifespan begins and ends.

Chunyan He of the Harvard School of Public Health and her colleagues scanned the genomes of more than 17,000 women, looking for genetic sequences associated with age at menarche — the start of the first menstrual cycle. They found a series of genetic markers associated with the onset of sexual maturity, including several clustered in and near a gene called LIN28B, and additional markers associated with the timing of menopause.

Another project, by Patrick Sulem and Kari Stefansson of deCODE Genetics in Reykjavik and their collaborators, also found a link between LIN28B and the onset of puberty. Meanwhile, a third study from Ken Ong and Ruth Loos of Addenbrooke's Hospital in Cambridge, UK, and their colleagues reports a particular form of the gene that is associated with earlier menarche and breast development in girls, and earlier voice-breaking in boys.



Animal behaviour: Pretty please



Photo: R. WITTEK/GETTY (Nature)


Many young animals beg for food from their elders. But, eventually, the pleading stops or the charity dries up. Joah Madden, at the University of Cambridge, UK, and his team looked to find the biological triggers that put an end to begging behaviour by studying free-ranging meerkats (Suricata suricatta) of the Kalahari Desert in South Africa over an 18-month period.
The group analysed the begging calls of meerkat pups aged between 40 and 60 days — the peak of their begging behaviour — and compared them with the calls of the same individuals aged 100–120 days. Experimental playback to adults revealed that lower-pitched juvenile calls reaped fewer rewards than the pleading of pups.