Tammar wallaby’s clever immune tricks revealed

Jul 11, 2011
Tammar wallaby’s clever immune tricks revealed
A Tammar wallaby. Credit: AGRF/Vicci Crowley-Clough

(PhysOrg.com) -- Until now, it was a mystery why many marsupials have two thymuses—key organs in the immune system—instead of the one typical of other mammals. Now postdoctoral researcher Dr. Emily Wong from the University of Sydney and her colleagues have found that the two organs are identical, which suggests why they are there.

“The presence of two organs with identical function can allow the young to produce white blood cells rapidly, leading to faster development of immune defences,” Emily says. “This may be especially critical in , as they are born at an immature stage without immune tissues. They need to develop an immune system very quickly while growing in the pouch.”

“It used to be believed that the marsupial immune system was more primitive than that of humans and other mammals,” Emily says. “But, in fact, some aspects of the marsupial immune system appear more complex than our own—the two thymuses, for instance.”

Humans and most other mammals have only one thymus, the immune organ which produces T cells, the white blood cells that act as sentries to protect us from infection. The presence of multiple thymuses was an evolutionary mystery.

A Tammar wallaby joey in the pouch. Credit: AGRF/Vicci Crowley-Clough

Using the latest DNA sequencing technology, Emily explored the genetic contents of the two organs in the Tammar wallaby. “The sequencing allowed us to compare the genetic material in the two thymuses quickly and thoroughly,” she said. “And we found they were the same.”

The researchers selected the Tammar wallaby because it was the first Australian marsupial to have its entire genome sequenced and published. “The availability of the genome has allowed for unprecedented insights into the marsupial immune system,” Emily says. The Tammar wallaby genome project is a joint collaboration between Australian and US scientists.

Emily’s research is part of a larger, ongoing project to understand how newborn marsupials survive in dirty pouches without an .

Explore further: Danish museum discovers unique gift from Charles Darwin

add to favorites email to friend print save as pdf

Related Stories

Marijuana use suppresses immune functions, study shows

Dec 03, 2010

(PhysOrg.com) -- Smoking marijuana can trigger a suppression of the body’s immune functions, making cannabis users more susceptible to certain types of cancers and infections, according to a new study led by a University ...

Beating cancer with immune cells

Mar 04, 2011

The fight against cancer has received a significant boost with a medical breakthrough by researchers at The Australian National University.

Multi-layered armor protects body against immune failure

Jul 06, 2011

The human body incorporates multiple fail-safe mechanisms to protect it against the "friendly fire" from its immune system known as autoimmune disease, Charis Teh and colleagues at the John Curtin School of ...

Researchers discover way to reverse immune system aging

Jan 27, 2011

Researchers at the Technion-Israel Institute of Technology have discovered a way to reverse the aging process by removing old B lymphocytes (a type of white blood cell in the vertebrate immune system) from ...

Recommended for you

Danish museum discovers unique gift from Charles Darwin

Aug 29, 2014

The Natural History Museum of Denmark recently discovered a unique gift from one of the greatest-ever scientists. In 1854, Charles Darwin – father of the theory of evolution – sent a gift to his Danish ...

Top ten reptiles and amphibians benefitting from zoos

Aug 29, 2014

A frog that does not croak, the largest living lizard, and a tortoise that can live up to 100 years are just some of the species staving off extinction thanks to the help of zoos, according to a new report.

User comments : 0