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 July 25, 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 July 25, 2014).

Share This




More Fossils & Ruins News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Did ISIS Destroy Jonah's Tomb?

Did ISIS Destroy Jonah's Tomb?

Newsy (July 25, 2014) Unverified footage posted to YouTube purportedly shows ISIS militants destroying a shrine widely believed to be the tomb of the prophet Jonah. Video provided by Newsy
Powered by NewsLook.com
Mobile App Gives Tour of Battle of Atlanta Sites

Mobile App Gives Tour of Battle of Atlanta Sites

AP (July 25, 2014) Emory University's Center for Digital Scholarship has launched a self-guided mobile tour app to coincide with the 150th anniversary of the Civil War's Battle of Atlanta. (July 25) Video provided by AP
Powered by NewsLook.com
Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Newsy (July 24, 2014) A new study claims a set of prehistoric T-Rex footprints supports the theory that the giant predators hunted in packs instead of alone. Video provided by Newsy
Powered by NewsLook.com
Mint Gives JFK Coin a Face-Lift

Mint Gives JFK Coin a Face-Lift

AP (July 24, 2014) The U.S. Mint has re-designed the John F. Kennedy half dollar coin to better match the former president's likeness. (July 24) 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