© Eurekalert

Tiger conservation, already one of the world's toughest tasks, may have got even more complicated. A genetic analysis of more than 130 tigers, published today, has turned up a new subspecies of the endangered big cat.

Sadly, however, this does not mean that there are actually more tigers. The new subspecies, named Panthera tigris jacksoni, comes from dividing an existing subspecies into two distinct genetic groups.

The cats remain perilously endangered. Most estimates put the total number of tigers left in the wild at less than 7,000. Having once roamed much of Asia, they have been hunted to the brink of oblivion, a process fuelled by the illegal trade in tiger parts.

Conservationists think that, of the eight traditional subspecies, three have completely died out since the 1940s; these are the Bali, Caspian and Java tigers. This has left five small bands of tigers: in Siberia, southern China, Sumatra, the Indian subcontinent and Indochina.

Indochinese tigers should properly be thought of as two separate subspecies, according to the genetic analysis by Shu-Jin Luo, of the US National Cancer Institute's Laboratory of Genomic Diversity in Maryland, and her colleagues. Those that live on the Malay Peninsula and those that live in more northerly parts of Indochina are two distinct groups, the team reports in an online version of the journal PLoS Biology¹.

Of a different stripe

The researchers collected tiger DNA from all over Asia to see whether the traditional subspecies groupings, based on geographical location, size and stripe patterns, are reflected in genetic diversity. The only discrepancy they found is that the Malaysian tigers, previously lumped in with P. tigris corbetti, deserve their own name, P. tigris jacksoni.

The researchers chose the name to honour the work of tiger conservationist Peter Jackson. And the study's publication closes the book on a debate that has simmered since the work was first presented at the South-East Asia Zoo Association's conference in Hong Kong in September. Malaysian conservationists had argued that the subspecies should be christened P. tigris malayensis.

In the conference's aftermath, Mohd Nawayai Yasak, chairman of the Malaysian Association of Zoological Parks and Aquaria, commented that: "Naming is important... more so for the tiger, which is our flagship species."

The researchers have now agreed that, while the name jacksoni will stay, the tiger should be known commonly as the Malayan tiger, in keeping with the regional monikers of other tiger subspecies such as the Bengal and Sumatran.

Conserving tigers

The tiger is a potent symbol for conservationists. "Tigers are one of the biggest and most charismatic endangered species. They're icons," agrees Stephen O'Brien, head of the Laboratory of Genomic Diversity.

The researchers' discovery is set to help guide conservation efforts, both in the wild and in captivity, O'Brien suggests. Although tiger subspecies can interbreed, it may be better to breed like with like, to preserve features such as body size that may help the various groups to survive in their different habitats.

Genetic techniques could also help investigators to trace the origins of any tiger parts confiscated from black-market dealers, O'Brien adds. "We're excited about the power of these molecular tools," he says. 

Laboratory of Genomic Diversity, US National Cancer Institute

• References

  1. Luo S. J., et al. PLoS Biology, 2. e442 (2004). | PubMed |