Featured Research

from universities, journals, and other organizations

Scat reveals an immigrant in Isle Royale wolves' gene pool

Date:
March 31, 2011
Source:
Michigan Technological University
Summary:
Until recently scientists studying the wolves of Isle Royale National Park thought they'd been totally isolated on the Lake Superior island for more than half a century. Now, by analyzing droppings, they've found the DNA of a fairly recent immigrant wolf from Canada.

The large, lighter colored wolf in the center is the immigrant from Canada dubbed The Old Gray Guy. The wolf to the left is his daughter and mate, who died during 2010.
Credit: John Vucetich

The wolves and moose of Isle Royale have done it again. They've surprised the scientists who have spent more than half a century studying them.

In a journal article published online March 31 in the Proceedings of the Royal Society and in their 2010-2011 annual report, Michigan Technological University researchers John A. Vucetich and Rolf O. Peterson tell an unexpected tale of genetic immigration. In 1997, a virile male wolf crossed an ice bridge from Canada to the remote island national park in northern Lake Superior. He was physically larger than most Isle Royale wolves, and soon after his arrival he became the alpha male of Middle Pack, one of the island's three packs. As he aged, his fur turned very light, a trait that had not been seen previously on Isle Royale, but has since become common. Before knowing his genetic history, the researchers called this wolf "The Old Gray Guy."

How did Vucetich and Peterson learn so much about The Old Gray Guy? For the past 12 years, they had been systematically collecting scat (poop or droppings) deposited by the wolves. The immigrant wolf was discovered after Vucetich and Peterson collaborated with geneticists Jennifer Adams and Leah Vucetich from Michigan Tech and Phil Hedrick of Arizona State University, to examine the DNA contained within the scat. The geneticists found a scat that carried several alleles -- alternative forms of a gene -- that had not previously been seen in Isle Royale wolves. Through field observations, Peterson and Vucetich confirmed that this scat belonged to The Old Gray Guy.

The research was funded by the National Science Foundation (NSF) and the US National Park Service.

"Before this discovery, the Isle Royale wolf population had been considered completely isolated since it was founded in the late 1940s," Vucetich says.

According to the researchers, the discovery is also an important opportunity to better understand genetic rescue, a potentially important conservation tool for populations that suffer from inbreeding. Genetic rescue involves introducing one or more unrelated individuals into an inbred population. The effectiveness of genetic rescue is not well understood because the opportunities are limited to closely monitor an isolated population before and after a known immigration event. For this reason, the Isle Royale immigrant represents a special opportunity.

Genetic rescue is supposed to result in increased survival or reproduction. However, evidence for increased birth or longevity rates in the Isle Royale population is equivocal. Coincident with the immigrantʼs arrival, though, moose on Isle Royale declined dramatically in response to food shortage, severe winters and tick outbreaks. A clear response to the immigration event may well have been disguised by lack of food for the wolves, the scientists suggest. If so, it may be important to recognize that deteriorating ecological conditions can mask the beneficial effects of infusing new genetic material, they point out.

The Old Gray Guy died in 2006. But he left his mark. He sired 34 offspring and 22 grand-offspring, "and counting," the scientists say. Today, 56 percent of all the genes now found in the Isle Royale wolf population trace back to him. Within a couple of generations of the Old Gray Guy's arrival, inbreeding plummeted, but then rose quickly again. This Isle Royale case shows how the effect of genetic rescue can be substantial and manifest quickly, but also be short-lived.

Wolf Population Declining

The wolf-moose researchers' latest report also brings discouraging news about the wolves of Isle Royale. This year's Winter Study, conducted between Jan. 12 and Feb. 28, 2011, found that the Isle Royale wolf population had been reduced to just 16 wolves. Among these wolves are no more than two adult females. If the few remaining females were to die before raising female pups, the wolf population would almost certainly be committed to extinction. "The situation is kind of precarious," says Vucetich. "But it's always been precarious," Peterson notes.

The wolf population has also been reduced from the four packs seen a couple of years ago to perhaps just a single pack. East Pack and Paduka Pack went extinct in late 2009. In late February 2011, Chippewa Harbor Pack traveled deep into Middle Pack's territory, where they killed Middle Pack's alpha male (a son of the Old Gray Guy). "With his death, the survival of Middle Pack is doubtful," Vucetich and Peterson say. It has been 40 years since the wolf population was composed of just a single pack.

The scientists acknowledge that National Park Service (NPS) policy promotes natural processes, and that, in this instance, local application of NPS policy could mean natural extinction. However, they advocate for an evaluation of the full range of management options, including the introduction of new wolves into the inbred population on Isle Royale.

Moose are Thriving

During the 2011 Winter Study, the scientists estimated a population of 515 moose, approximately the same as it has been for the past three years.

With the number of moose remaining low for so long now, the vegetation on Isle Royale also has become more abundant. Balsam firs, a favorite meal for moose, are growing taller than ever before, and deciduous shrubs have been flourishing. The calves were larger this winter, and the fat content of bone marrow indicates that adult moose are better nourished now. The scientists have spotted three sets of twins in the past two years, the first twins since 2005. Winter ticks, which posed a severe threat to the Isle Royale moose in 2007, have declined significantly since then.

"The moose are poised for increase," says Peterson. The last large increase in the moose population was seen on Isle Royale in the 1990s.


Story Source:

The above story is based on materials provided by Michigan Technological University. The original article was written by Jennifer Donovan. Note: Materials may be edited for content and length.


Journal Reference:

  1. J. R. Adams, L. M. Vucetich, P. W. Hedrick, R. O. Peterson, J. A. Vucetich. Genomic sweep and potential genetic rescue during limiting environmental conditions in an isolated wolf population. Proceedings of the Royal Society B: Biological Sciences, 2011; DOI: 10.1098/rspb.2011.0261

Cite This Page:

Michigan Technological University. "Scat reveals an immigrant in Isle Royale wolves' gene pool." ScienceDaily. ScienceDaily, 31 March 2011. <www.sciencedaily.com/releases/2011/03/110331142219.htm>.
Michigan Technological University. (2011, March 31). Scat reveals an immigrant in Isle Royale wolves' gene pool. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2011/03/110331142219.htm
Michigan Technological University. "Scat reveals an immigrant in Isle Royale wolves' gene pool." ScienceDaily. www.sciencedaily.com/releases/2011/03/110331142219.htm (accessed October 21, 2014).

Share This



More Plants & Animals News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

'Cadaver Dog' Sniffs out Human Remains

'Cadaver Dog' Sniffs out Human Remains

AP (Oct. 21, 2014) Where's a body buried? Buster's nose can often tell you. He's a cadaver dog, specially trained to find human remains and increasingly being used by law enforcement and accepted in courts. These dogs are helping solve even decades-old mysteries. (Oct. 21) Video provided by AP
Powered by NewsLook.com
White Lion Cubs Born in Belgrade Zoo

White Lion Cubs Born in Belgrade Zoo

AFP (Oct. 20, 2014) Two white lion cubs, an extremely rare subspecies of the African lion, were recently born at Belgrade Zoo. They are being bottle fed by zoo keepers after they were rejected by their mother after birth. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
Goliath Spider Will Give You Nightmares

Goliath Spider Will Give You Nightmares

Buzz60 (Oct. 20, 2014) An entomologist stumbled upon a South American Goliath Birdeater. With a name like that, you know it's a terrifying creepy crawler. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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