Featured Research

from universities, journals, and other organizations

Living longer: Variability in infection-fighting genes can be a boon for male survival

Date:
May 11, 2012
Source:
University of Veterinary Medicine -- Vienna
Summary:
Scientists have found that male Alpine chamois heterozygous at a particular immune gene locus (i.e. who possess two different forms of that gene) survive significantly longer than homozygous individuals (i.e. those with two identical copies of the gene) but they found no such effect for female chamois.

A group of female and juvenile chamois.
Credit: Agnes Haymerle

Females of mammals (including humans) tend to outlive males, a circumstance that is usually attributed to males΄ more aggressive and hence energy-depleting behaviour, especially when they compete for females. This might also explain why males of many species usually show a higher parasite burden than females. Therefore, high variability of immune genes, supposed to reduce susceptibility to pathogens, may be more important for males.

Scientists at the Research Institute of Wildlife Ecology (FIWI) of the University of Veterinary Medicine, Vienna have now found that male Alpine chamois heterozygous at a particular immune gene locus (i.e. who possess two different forms of that gene) indeed survive significantly longer than homozygous individuals (i.e. those with two identical copies of the gene) but they found no such effect for female chamois.

The results are published in the current issue of the journal BMC Evolutionary Biology.

A heavy price to pay for love

It comes as no surprise to learn that males devote considerable efforts in wooing females. To understand just how costly their exertions are, Helmut Schaschl, Franz Suchentrunk, David L. Morris, Hichem Ben Slimen, Steve Smith, and Walter Arnold have undertaken a long-term study of survival patterns and their possible immune genetic basis in free-living populations of Alpine chamois (Rupicapra rupicapra).

Alpine chamois may live for 16 to 20 years in the wild, although male survival may decrease appreciably after the age of 11. This was the case in areas affected by scabies, a highly contagious disease that occurs in regular waves across large parts of the Eastern Alps. In these populations, reproductively active males have a higher death rate than females and younger males, presumably because the energetic challenge of the winter rut renders them more susceptible to the disease. "We found that the older chamois males depleted their body fat stores at the end of the harsh alpine winter about six weeks before females and younger males," says Walter Arnold, one of the authors. "With lower body fat reserves they have less energy to put into their immune systems. This might explain why the genetic component of immune defence is more important for males than for females."

Genetic diversity to the rescue

The scientists looked for features of the immune genes supposed to reduce susceptibility to pathogens. They analysed the variability (i.e. homo- vs. heterozygosity) of a gene of the major histocompatibility complex (MHC), which has an important role in recognizing infectious agents. In areas affected by scabies, the proportion of males heterozygous at that MHC gene increased with age, suggesting higher mortality of homozygous individuals. There was no such trend among females. Importantly, the survival of male chamois did not appear to be related to heterozygosity in general but only to the heterozygosity of the MHC gene. This makes sense, as different immune gene variants within an individual potentially recognise a broader spectrum of pathogens and thus confer an enhanced immunity on the animal.

"Apparently, the higher energy expenditure of rutting males only becomes a problem when their immune system is heavily challenged. In this situation the males with heterozygous immune genes seem to have a distinct survival advantage," explains Arnold. The research results thus point to a sex-specific fitness benefit of the variability of MHC genes.


Story Source:

The above story is based on materials provided by University of Veterinary Medicine -- Vienna. Note: Materials may be edited for content and length.


Journal Reference:

  1. Helmut Schaschl, Franz Suchentrunk, David L Morris, Hichem Slimen, Steve Smith, Walter Arnold. Sex-specific selection for MHC variability in Alpine chamois. BMC Evolutionary Biology, 2012; 12 (1): 20 DOI: 10.1186/1471-2148-12-20

Cite This Page:

University of Veterinary Medicine -- Vienna. "Living longer: Variability in infection-fighting genes can be a boon for male survival." ScienceDaily. ScienceDaily, 11 May 2012. <www.sciencedaily.com/releases/2012/05/120511104157.htm>.
University of Veterinary Medicine -- Vienna. (2012, May 11). Living longer: Variability in infection-fighting genes can be a boon for male survival. ScienceDaily. Retrieved April 24, 2014 from www.sciencedaily.com/releases/2012/05/120511104157.htm
University of Veterinary Medicine -- Vienna. "Living longer: Variability in infection-fighting genes can be a boon for male survival." ScienceDaily. www.sciencedaily.com/releases/2012/05/120511104157.htm (accessed April 24, 2014).

Share This



More Plants & Animals News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Fungus Killing Bats, Spreading in US

Deadly Fungus Killing Bats, Spreading in US

AP (Apr. 24, 2014) — A disease that has killed more than six million cave-dwelling bats in the United States is on the move and wildlife biologists are worried. White Nose Syndrome, discovered in New York in 2006, has now spread to 25 states. (April 24) Video provided by AP
Powered by NewsLook.com
Monkeys Are Better At Math Than We Thought, Study Shows

Monkeys Are Better At Math Than We Thought, Study Shows

Newsy (Apr. 23, 2014) — A Harvard University study suggests monkeys can use symbols to perform basic math calculations. Video provided by Newsy
Powered by NewsLook.com
Raw: Leopard Bites Man in India

Raw: Leopard Bites Man in India

AP (Apr. 22, 2014) — A leopard caused panic in the city of Chandrapur on Monday when it sprung from the roof of a house and charged at rescue workers. (April 22) Video provided by AP
Powered by NewsLook.com
Iowa College Finds Beauty in Bulldogs

Iowa College Finds Beauty in Bulldogs

AP (Apr. 22, 2014) — Drake University hosts 35th annual Beautiful Bulldog Contest. (April 21) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins