Showing posts with label spiny rat. Show all posts
Showing posts with label spiny rat. Show all posts

Thursday, 21 February 2019

What causes rats without a Y chromosome to become male?


Date:  January 31, 2019
Source:  Hokkaido University
A look at the brains of an endangered spiny rat off the coast of Japan by University of Missouri (MU) Bond Life Sciences Center scientist Cheryl Rosenfeld could illuminate the subtle genetic influences that stimulate a mammal's cells to develop as male versus female in the absence of a Y chromosome.
The root of the answer is in the chromosomes of this particular mammal. Males of the Amami spiny rat (Tokudaia osimensis) are not like most therian mammals -- a name used to group animals that give live birth including placental mammals and marsupials. Unlike in most mammals, these males have no Y chromosome, which has been shed over eons of evolution. And they only have one X chromosome.
"I'd been interested in these rats for many years now, and it's unclear how sexual differentiation of the gonads and brain occur in this species since both males and females have a single X chromosome," said Cheryl Rosenfeld, lead author on the study and an MU researcher.

Sunday, 22 September 2013

New spiny rat discovered in 'birthplace of evolution'

Tufts of harsh, bristly hair and a white tail tip are among the defining features of a new rodent species discovered in Indonesia.

The Spiny Boki Mekot Rat was found in the mountain forests of Halmahera, in the Moluccas (Maluku) archipelago.

It was from these islands that Alfred Russel Wallace wrote to Charles Darwin, outlining his theory of evolution.

The region is rich in biodiversity but its wildlife is under threat from logging and mining firms.

Scientists hope the new mammal discovery will encourage greater exploration and conservation of the area.

Their findings are reported in the Zoological Journal of the Linnean Society.

Under threat
The new rat was found in a remote, hilly region of Halmahera by an expedition team from the University of Copenhagen and Indonesia's Museum Zoologicum Bogoriense.

They laid traps baited with roasted coconut and peanut butter, placed on tree trunks and at burrow openings.

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