Featured Research

from universities, journals, and other organizations

Selective imprinting: how the wallaby controls growth of its young

Date:
August 27, 2012
Source:
BioMed Central Limited
Summary:
Marsupial mothers regulate the composition of their milk so that it is optimal for the development stage of their young. New research shows that, similar to the human placenta, which regulates embryonic growth and development, insulin appears to be imprinted in the marsupial mammary gland.

Marsupial mothers regulate the composition of their milk so that it is optimal for the development stage of their young.
Credit: Geoffrey Shaw

Marsupial mothers regulate the composition of their milk so that it is optimal for the development stage of their young. New research published in BioMed Central's open access journal Epigenetics & Chromatin shows that, similar to the human placenta, which regulates embryonic growth and development, insulin appears to be imprinted in the marsupial mammary gland.

Insulin is well known as the hormone which regulates blood sugar levels but it also essential for proper functioning of the nervous system, protein synthesis, and for cell growth and survival. It is also required for lactation in mammals and, along with insulin growth factor 2 (IGF2), is present in milk.

Imprinting is a way of controlling gene expression. To ensure only one copy of a certain gene is active (monoallelic), the other copy is silenced, usually by methylation. Imprinting is established during sperm or egg production so that the developing embryo inherits paternally imprinted genes from its father, and maternally imprinted from its mother. Consequently the active copy is inherited only from either the mother or father. However this is complicated by imprinting being both tissue specific and dependent on the stage of development.

Insulin was thought to be only imprinted in the yolk sac of mice and humans and only in the wallaby yolk sac placenta, however, in marsupials much of this growth and development occurs after birth and is controlled instead by milk that changes composition throughout lactation. The University of Melbourne looked at whether the gene wallaby mammary gland is similarly imprinted, if it was also imprinted in the pouch young (joey), and whether this imprinting was maternally or paternally inherited.

The team found that insulin gene (INS) expression in the adult tammar wallaby mammary gland was monoallelic (one active copy), indicating imprinting and that this active copy came from the father. Paternally inherited monoallelic INS expression was also discovered in both the adult and the young tammar liver, but not in other tissues tested. IGF2 was also monoallelic in the mammary gland but the relative expression of INS and IGF2 differed during lactation. IGF2 expression in the mammary gland decreased after the first few days but INS expression increased as the babies became more mature especially between 5 and 14 weeks of age.

Prof Marilyn Renfree, who led this project commented, "This is the first indication that genomic imprinting occurs in the marsupial mammary gland and suggests that genomic imprinting in the mammary gland may be as critical for regulating post-natal growth as it is for regulating pre-natal growth in the placenta in all mammals."


Story Source:

The above story is based on materials provided by BioMed Central Limited. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jessica M Stringer, Shunsuke Suzuki, Andrew J Pask, Geoff Shaw and Marilyn B Renfree. Selected imprinting of INS in the marsupial. Epigenetics & Chromatin, 2012 (in press) [link]

Cite This Page:

BioMed Central Limited. "Selective imprinting: how the wallaby controls growth of its young." ScienceDaily. ScienceDaily, 27 August 2012. <www.sciencedaily.com/releases/2012/08/120827205740.htm>.
BioMed Central Limited. (2012, August 27). Selective imprinting: how the wallaby controls growth of its young. ScienceDaily. Retrieved July 22, 2014 from www.sciencedaily.com/releases/2012/08/120827205740.htm
BioMed Central Limited. "Selective imprinting: how the wallaby controls growth of its young." ScienceDaily. www.sciencedaily.com/releases/2012/08/120827205740.htm (accessed July 22, 2014).

Share This




More Plants & Animals News

Tuesday, July 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Michigan Plant's Goal: Flower and Die

Michigan Plant's Goal: Flower and Die

AP (July 22, 2014) An 80-year-old agave plant, which is blooming for the first and only time at a University of Michigan conservatory, will die when it's done (July 22) Video provided by AP
Powered by NewsLook.com
San Diego Zoo Welcomes New, Rare Rhino Calf

San Diego Zoo Welcomes New, Rare Rhino Calf

Reuters - US Online Video (July 21, 2014) An endangered black rhino baby is the newest resident at the San Diego Zoo. Sasha Salama reports. Video provided by Reuters
Powered by NewsLook.com
Shark Sightings a Big Catch for Cape Tourism

Shark Sightings a Big Catch for Cape Tourism

AP (July 21, 2014) A rise in shark sightings along the shores of Chatham, Massachusetts is driving a surge of eager vacationers to the beach town looking to catch a glimpse of a great white. (July 21) Video provided by AP
Powered by NewsLook.com
$23.6 Billion Awarded To Widow In Smoking Lawsuit

$23.6 Billion Awarded To Widow In Smoking Lawsuit

Newsy (July 20, 2014) Cynthia Robinson claims R.J. Reynolds Tobacco Company hid the health and addiction risks of its products, leading to the death of her husband in 1996. 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:
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