Featured Research

from universities, journals, and other organizations

More than just X and Y: New genetic basis for sex determination

Date:
August 18, 2014
Source:
Cold Spring Harbor Laboratory
Summary:
Men and women differ in obvious ways, and scientists have long known that genetic differences buried deep within our DNA underlie these distinctions. In the past, most research has focused on understanding how the genes that encode proteins act as sex determinants. But scientists have found that a subset of very small genes encoding short RNA molecules, called microRNAs, also play a key role in differentiating male and female tissues in the fruit fly.

Cold Spring Harbor Laboratory researchers have found that miRNAs, short RNA molecules, are responsible for sexual differences in fruit flies. Shown here are testes from a male fruit fly where a hormone that controls a key miRNA has been inactivated. The abnormal testes fail to make sperm. They now produce sex determinants (shown in red) that are found in the ovaries of female flies.
Credit: D. Fagegaltier/ Cold Spring Harbor Laboratory

Men and women differ in plenty of obvious ways, and scientists have long known that genetic differences buried deep within our DNA underlie these distinctions. In the past, most research has focused on understanding how the genes that encode proteins act as sex determinants. But Cold Spring Harbor Laboratory (CSHL) scientists have found that a subset of very small genes encoding short RNA molecules, called microRNAs (miRNAs), also play a key role in differentiating male and female tissues in the fruit fly.

A miRNA is a short segment of RNA that fine-tunes the activation of one or several protein-coding genes. miRNAs are able to silence the genes they target and, in doing so, orchestrate complex genetic programs that are the basis of development.

In work published in Genetics, a team of CSHL researchers and colleagues describe how miRNAs contribute to sexual differences in fruit flies. You've probably never noticed, but male and female flies differ visibly, just like other animals. For example, females are 25% larger than males with lighter pigmentation and more abdominal segments.

The team of researchers, including Delphine Fagegaltier, PhD, lead author on the study, and CSHL Professor and Howard Hughes Medical Institute Investigator Greg Hannon, identified distinct miRNA populations in male and female flies. "We found that the differences in miRNAs are important in shaping the structures that distinguish the two sexes," says Fagegaltier. "In fact, miRNAs regulate the very proteins that act as sex determinants during development."

The team found that miRNAs are essential for sex determination even after an animal has grown to adulthood. "They send signals that allow germ cells, i.e., eggs and sperm, to develop, ensuring fertility," Fagegaltier explains. "Removing one miRNA from mature, adult flies causes infertility." More than that, these flies begin to produce both male and female sex-determinants. "In a sense, once they have lost this miRNA, the flies become male and female at the same time," according to Fagegaltier. "It is amazing that the very smallest genes can have such a big effect on sexual identity."

Some miRNAs examined in the study, such as let-7, have been preserved by evolution because of their utility; humans and many other animals carry versions of them. "This is probably just the tip of the iceberg," says Fagegaltier. "There are likely many more miRNAs regulating sexual identity at the cellular and tissue level, but we still have a lot to learn about these differences in humans, and how they could contribute to developmental defects and disease."


Story Source:

The above story is based on materials provided by Cold Spring Harbor Laboratory. Note: Materials may be edited for content and length.


Journal Reference:

  1. D. Fagegaltier, A. Konig, A. Gordon, E. C. Lai, T. R. Gingeras, G. J. Hannon, H. R. Shcherbata. A Genome-Wide Survey of Sexually Dimorphic Expression of Drosophila miRNAs Identifies the Steroid Hormone-Induced miRNA let-7 as a Regulator of Sexual Identity. Genetics, 2014; DOI: 10.1534/genetics.114.169268

Cite This Page:

Cold Spring Harbor Laboratory. "More than just X and Y: New genetic basis for sex determination." ScienceDaily. ScienceDaily, 18 August 2014. <www.sciencedaily.com/releases/2014/08/140818153601.htm>.
Cold Spring Harbor Laboratory. (2014, August 18). More than just X and Y: New genetic basis for sex determination. ScienceDaily. Retrieved September 14, 2014 from www.sciencedaily.com/releases/2014/08/140818153601.htm
Cold Spring Harbor Laboratory. "More than just X and Y: New genetic basis for sex determination." ScienceDaily. www.sciencedaily.com/releases/2014/08/140818153601.htm (accessed September 14, 2014).

Share This



More Plants & Animals News

Sunday, September 14, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

'Magic Mushrooms' Could Help Smokers Quit

'Magic Mushrooms' Could Help Smokers Quit

Newsy (Sep. 11, 2014) — In a small study, researchers found that the majority of long-time smokers quit after taking psilocybin pills and undergoing therapy sessions. Video provided by Newsy
Powered by NewsLook.com
Spinosaurus Could Be First Semi-Aquatic Dinosaur

Spinosaurus Could Be First Semi-Aquatic Dinosaur

Newsy (Sep. 11, 2014) — New research has shown that the Spinosaurus, the largest carnivorous dinosaur, might have been just as well suited for life in the water as on land. Video provided by Newsy
Powered by NewsLook.com
Meet Spinosaurus, the First-Known Water Dinosaur

Meet Spinosaurus, the First-Known Water Dinosaur

AFP (Sep. 11, 2014) — Spinosaurus aegyptiacus was adapted for both land and water, and an exhibit featuring a life-sized model, based on new fossils unearthed in eastern Morocco, opens at the National Geographic Museum in Washington on Friday. Duration: 01:02 Video provided by AFP
Powered by NewsLook.com
Clouded Leopards Make Houston Zoo Debut

Clouded Leopards Make Houston Zoo Debut

AP (Sep. 11, 2014) — Two clouded leopard cubs made their public debut at the Houston Zoo Thursday. The pair delighted crowds by climbing trees, wrestling, turning and jumping throughout their habitat. (Sept. 11) 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