Featured Research

from universities, journals, and other organizations

Evolution Of An Imprinted Domain In Mammals

Date:
June 3, 2008
Source:
Public Library of Science
Summary:
A new article investigates the evolution of genomic imprinting in a specific region of the mammalian genome. The work shows that different regions became imprinted at different times during mammalian evolution.

The normal human genome contains 46 chromosomes: 23 from the mother and 23 from the father. Thus, you have two copies of every gene (excluding some irregularity in the pair of sex chromosomes). In general, which parent contributes a chromosome has no effect on the expression of the genes found on it. Exceptions to this rule are caused by "genomic imprinting"--modification of DNA, which means that gene expression is influenced by which parent the gene came from. A new paper investigates the evolution of genomic imprinting in a specific region of the mammalian genome. The work, by Anne Ferguson-Smith and colleagues in the UK and Australia, shows that different regions became imprinted at different times during mammalian evolution.

Genomic imprinting is hypothesized to have evolved because of the conflicting interests of mother and father relating to offspring development. In some conditions where two parents contribute to producing young together, each parent benefits evolutionarily by coercing the other into investing more in the baby--because the investment will benefit their own genes (in the form of their child) and cost an individual that is genetically unrelated--the mate.

Therefore, genes in the father may benefit from producing a placenta that demands a lot of maternal resources, and thus there would be a selection pressure to modify sperm--but not eggs--so that the genes they carry are expressed in a way that builds a demanding placenta. Indeed, in mammals, imprinting seems to have arisen in line with the evolution of the placenta and the new work by Ferguson-Smith et al. supports this.

There are three existing lineages of mammals: placental mammals (including humans), marsupial mammals (which have a simpler form of placenta, and include kangaroos, koalas, etc.), and monotremes (egg laying mammals, e.g. the duck-billed platypus). When comparing these three mammalian groups at a specific region of the genome (called Dlk1-Dio3), Ferguson-Smith et al. found that imprinting occurred only in placental mammals.

This finding contrasts previous work, which has found regions imprinted in both marsupials and placentals, but not in monotremes. Thus, together with previous work, Ferguson-Smith et al. have shown that imprinting of the mammalian genome occurred gradually; some genes becoming differentially expressed before the marsupial-placental common ancestor and others afterwards. That different regions changed at different times suggests that these changes were in response to selection pressures and therefore are adaptive--beneficial to survival/reproductive fitness rather than a by-product of another process.

Interestingly, the genetic comparisons Ferguson-Smith and colleagues have made show that imprinting correlates with highly repetitive regions of DNA. In marsupials, the Dlk1-Dio3 region is double the length found in placental mammals, due to random insertion of non-coding DNA, whereas in the different placental lineages, the region has very little non-coding sequence.


Story Source:

The above story is based on materials provided by Public Library of Science. Note: Materials may be edited for content and length.


Journal Reference:

  1. Edwards et al. The evolution of the DLK1-DIO3 imprinted domain in mammals. PLoS Biology, 2008; 6 (6): e135 DOI: 10.1371/journal.pbio.0060135

Cite This Page:

Public Library of Science. "Evolution Of An Imprinted Domain In Mammals." ScienceDaily. ScienceDaily, 3 June 2008. <www.sciencedaily.com/releases/2008/06/080602214249.htm>.
Public Library of Science. (2008, June 3). Evolution Of An Imprinted Domain In Mammals. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2008/06/080602214249.htm
Public Library of Science. "Evolution Of An Imprinted Domain In Mammals." ScienceDaily. www.sciencedaily.com/releases/2008/06/080602214249.htm (accessed September 17, 2014).

Share This



More Fossils & Ruins News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Egypt Denies Claims Oldest Pyramid Damaged in Restoration

Egypt Denies Claims Oldest Pyramid Damaged in Restoration

AFP (Sep. 17, 2014) Egypt's antiquities minister denied Tuesday claims that the Djoser pyramid, the country's first, had been damaged during restoration work by a company accused of being unqualified to do such work. Duration: 00:56 Video provided by AFP
Powered by NewsLook.com
King Richard III's Painful Cause Of Death Revealed

King Richard III's Painful Cause Of Death Revealed

Newsy (Sep. 17, 2014) King Richard III died in the Battle of Bosworth in 1485, and now researchers examining his skull think they know how. Video provided by Newsy
Powered by NewsLook.com
Researchers Explore Shipwrecks Off Calif. Coast

Researchers Explore Shipwrecks Off Calif. Coast

AP (Sep. 16, 2014) Federal researchers are exploring more than a dozen underwater sites where they believe ships sank in the treacherous waters west of San Francisco in the decades following the Gold Rush. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Museum Traces Fragments of Star-Spangled Banner

Museum Traces Fragments of Star-Spangled Banner

AP (Sep. 12, 2014) As the Star-Spangled Banner celebrates its bicentennial, Smithsonian curators are still uncovering fragments of the original flag that inspired Francis Scott Key's poem. (Sept. 12) 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