Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study of Shark Virgin Birth Shows Offspring Can Survive Long Term

26.01.2010
Shark pups born to virgin mothers can survive over the long-term, according to new research published Jan. 25, 2010 in the Journal of Heredity. The study shows for the first time that some virgin births can result in viable offspring.

Genetic analysis led by a Field Museum scientist working with numerous colleagues has confirmed the first known case of a virgin female shark producing multiple offspring that survived. Two daughters of the white-spotted bamboo shark are now more than five years old. Earlier research proved that reproduction occurred in two other shark species without aid of male sperm, a phenomenon called parthenogenesis, but the offspring did not survive in those cases.

Dr. Kevin Feldheim, manager of the Pritzker Laboratory for Molecular Systematics and Evolution at the Field Museum, analyzed the sharks’ genetic material to rule out any paternal reproduction assistance.

“Examination of highly variable sections of the genome prove that these young sharks had no father,” Feldheim said. “These findings are remarkable because they tell us that some female sharks can produce litters of offspring without ever having mated with a male.

“We compared several sections of the genome between two of the young sharks and their mother. It turned out that all the genetic material in each of the young ones came from the mother, proving there was no father.”

Although the shark mother was kept in a tank at the Belle Isle Aquarium in Detroit where only another female of a different but related species resided, genetic testing was required to rule out the possibility that the female shark could have encountered male sperm earlier in her life.

A second analysis using more general techniques to examine more than a hundred additional regions of the genome was performed by Séan Fitzpatrick, Ph.D. Student, and Dr. Paulo Prodöhl, head of the Fish Genetics and Molecular Ecology Laboratory, of Queen’s University in Belfast, to confirm Feldheim’s finding.The analysis found that the young sharks didn’t share all their mother’s genetic material and aren’t true clones of her, but more like “half-clones,” said Feldheim.

Parthenogenesis occurs when an egg or ovum fuses with a cell called a sister polar body, a byproduct of ova production, rather than with male sperm, to promote cell division. The sister polar body is nearly genetically identical to the ovum, said Dr. Demian Chapman of the Institute for Ocean Conservation Science at Stony Brook University, co-author of the current study and lead author in earlier studies of virgin shark births.

Despite the lack of genetic diversity involved in omitting sperm from the process, “parthenogenesis may not be as much of a dead-end mode of reproduction as we thought for these sharks,” Chapman said.

Douglas Sweet, who formerly worked at the Detroit aquarium, decided to incubate the bamboo shark eggs when he discovered an apparent virgin had produced them because of earlier experiences elsewhere that suggested virgin shark reproduction.

Sweet, now superintendent of the London State Fish Hatchery in London, Ohio, said that studies have confirmed asexual reproduction in sharks that bear offspring live and those that deposit eggs. This leads to interesting genetic and conservation implications.

It could mean that a bamboo shark finding herself isolated on a small reef with no male in the vicinity could produce offspring in hopes that male suitors may eventually find their way to her daughters. “Sharks have been around for hundreds of millions of years,” Sweet said. “I suspect they have some pretty interesting survival strategies that we are only now becoming aware of.”

Kathryn Cervino | Newswise Science News
Further information:
http://www.stonybrook.edu

More articles from Studies and Analyses:

nachricht Real-time feedback helps save energy and water
08.02.2017 | Otto-Friedrich-Universität Bamberg

nachricht The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Switched-on DNA

20.02.2017 | Materials Sciences

Second cause of hidden hearing loss identified

20.02.2017 | Health and Medicine

Prospect for more effective treatment of nerve pain

20.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>