Featured Research

from universities, journals, and other organizations

Paternity testing helps fill in family tree for Puget Sound's killer whales: Inbreeding could reduce whales' genetic diversity

Date:
July 21, 2011
Source:
NOAA National Marine Fisheries Service
Summary:
Scientists using DNA testing to fill in a missing link in the lives of killer whales that seasonally visit Washington's Puget Sound, have discovered that some of the progeny they studied were the result of matings within the same social subgroups, or pods, that are part of the overall population.

Killer Whales (Orcinus orca).
Credit: NOAA

In a study published online this month in the Journal of Heredity, NOAA researchers and others, using DNA testing to fill in a missing link in the lives of killer whales that seasonally visit Washington's Puget Sound, have discovered that some of the progeny they studied were the result of matings within the same social subgroups, or pods, that are part of the overall population.

Related Articles


One implication of this inbreeding behavior is a significant reduction in the genetic diversity of what is already a perilously small population of animals, formally known as Southern Resident killer whales. That population numbers only about 85 animals and was listed as endangered under the federal Endangered Species Act in 2005.

Southern resident killer whales, which also visit the waters of British Columbia and are occasionally found as far south as Monterey Bay, Calif., consist of three pods called J, K and L pod. Inter-pod mating has never been detected in studies of Northern Resident killer whales, which range from Washington to southern Alaska, and until now researchers assumed that Southern Residents exhibited similar mating patterns. The two populations are distinct and do not socialize with each other.

The study, titled "Inferred paternity and male reproductive success in a killer whale (Orcinus orca) population," involved researchers from NOAA's Fisheries Service, the University of Washington, Cascadia Research Collective and the Center for Whale Research.

"We were surprised that, in many cases, the father was from the same pod as the mother. Based on earlier studies, we didn't think killer whales mated within their own pod," said Dr. Michael Ford, lead author of the study and a scientist with NOAA's Northwest Fisheries Science Center in Seattle.

"This behavior may be unique to the Southern Resident population, perhaps related to the population's small size," Ford added.

The researchers analyzed 78 individuals for 26 different genetic markers, or DNA fingerprints, and inferred the paternity for 15 mother-calf pairs. The study found no evidence that Southern Residents mate outside their population, but clear evidence that they do sometimes mate with members of their own pod.

"Even though some of the fathers were in the same pod as the mothers, none of them were really closely related to each other. Our results suggest that Southern Residents avoid mating with their siblings or parents, but we aren't really sure of the social process that results in this avoidance," Ford said.

Compared to many mammalian species, males within the Southern Resident community were also found to have a relatively low variance of reproductive success, meaning several males are responsible for offspring production in the population rather than just one or two. This contrasts with some other marine mammals like elephant seals, where a handful of males completely dominate the breeding and may reflect the difficulty male killer whales have in controlling other males' access to females.

However, the study also revealed that the older and larger males appeared to be responsible for most of the successful matings, indicating that females may choose to mate only with older males, or possibly that older males may prevent the younger males from breeding successfully.

Ford said he and his colleagues are particularly worried about the group's lack of genetic diversity, which he characterized as a "bottleneck." "Since this population remains isolated from other killer whale populations, mating within pods puts Southern Residents at risk of genetically deteriorating further from a potential increase in inbreeding or harmful mutations," he said.


Story Source:

The above story is based on materials provided by NOAA National Marine Fisheries Service. Note: Materials may be edited for content and length.


Journal Reference:

  1. M. J. Ford, M. B. Hanson, J. A. Hempelmann, K. L. Ayres, C. K. Emmons, G. S. Schorr, R. W. Baird, K. C. Balcomb, S. K. Wasser, K. M. Parsons, K. Balcomb-Bartok. Inferred Paternity and Male Reproductive Success in a Killer Whale (Orcinus orca) Population. Journal of Heredity, 2011; DOI: 10.1093/jhered/esr067

Cite This Page:

NOAA National Marine Fisheries Service. "Paternity testing helps fill in family tree for Puget Sound's killer whales: Inbreeding could reduce whales' genetic diversity." ScienceDaily. ScienceDaily, 21 July 2011. <www.sciencedaily.com/releases/2011/07/110721131206.htm>.
NOAA National Marine Fisheries Service. (2011, July 21). Paternity testing helps fill in family tree for Puget Sound's killer whales: Inbreeding could reduce whales' genetic diversity. ScienceDaily. Retrieved November 23, 2014 from www.sciencedaily.com/releases/2011/07/110721131206.htm
NOAA National Marine Fisheries Service. "Paternity testing helps fill in family tree for Puget Sound's killer whales: Inbreeding could reduce whales' genetic diversity." ScienceDaily. www.sciencedaily.com/releases/2011/07/110721131206.htm (accessed November 23, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Sunday, November 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

AFP (Nov. 23, 2014) The arable district of Kenema in Sierra Leone -- at the centre of the Ebola outbreak in May -- has been under quarantine for three months as the cocoa harvest comes in. Duration: 01:32 Video provided by AFP
Powered by NewsLook.com
Anglerfish Rarely Seen In Its Habitat Will Haunt You

Anglerfish Rarely Seen In Its Habitat Will Haunt You

Newsy (Nov. 22, 2014) For the first time Monterey Bay Aquarium recorded a video of the elusive, creepy and rarely seen anglerfish. Video provided by Newsy
Powered by NewsLook.com
Birds Around the World Take Flight

Birds Around the World Take Flight

Reuters - Light News Video Online (Nov. 22, 2014) An imperial eagle equipped with a camera spreads its wings over London. It's just one of the many birds making headlines in this week's "animal roundup". Jillian Kitchener reports. Video provided by Reuters
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
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