Featured Research

from universities, journals, and other organizations

Transgender algae reveal evolutionary origin of sexes

Date:
July 8, 2014
Source:
Public Library of Science
Summary:
Throughout evolution, living things have repeatedly developed physically distinct sexes, but how does this actually happen? A discovery in the multicellular green alga, Volvox carteri, has revealed the genetic origin of male and female sexes, showing how they evolved from a more primitive mating system in a single-celled relative. A team of scientists identified the master regulatory gene for sex determination in Volvox.

Throughout evolution, living things have repeatedly developed physically distinct sexes, but how does this actually happen? A discovery in the multicellular green alga, Volvox carteri, has revealed the genetic origin of male and female sexes, showing how they evolved from a more primitive mating system in a single-celled relative.

A team of scientists led by James Umen, Ph.D., Associate Member, Enterprise Institute for Renewable Fuels at the Danforth Plant Science Center, identified the master regulatory gene for sex determination in Volvox and found that it has acquired new functions compared to a related gene in its close relative, the unicellular alga Chlamydomonas reinhardtii, which does not have physically distinguishable (dimorphic) sexes. Their findings are publishing in the open access journal PLOS Biology on July 8, and may also provide a possible blueprint for how sexes in other multicellular organisms like plants and animals may have originated.

For plants and animals having male and female reproductive cells or gametes is the norm, and the differences between the two types of gametes are obvious. Male gametes are small motile sperm or pollen, while female gametes are large egg cells. However, the evolutionary origins of male and female sexes are unclear because the distant unicellular relatives of plants, animals and other multicellular species generally don't have distinct sexes, but instead have mating types -- a system in which gametes of one mating type can only fuse with those with a different mating type, but the cells of each mating type are indistinguishable from each other in size and morphology.

Unlike the case in plants and animals whose unicellular ancestors are very distantly related, male and female sexes in Volvox evolved relatively recently from mating types in an ancestor that was similar to Chlamydomonas. During a previous study, Umen and co-workers -- postdoctoral fellows Sa Geng and Peter DeHoff -- had identified a gene in Volvox males called MID whose counterpart in Chlamydomonas was known to control differentiation of its two mating types called "plus" and "minus."

By forcing genetically female Volvox to express MID, the team led by Umen was able to convert what would have been egg cells into packets of functional sperm cells. Conversely, by using a method of gene inactivation called RNA interference (RNAi), the Danforth scientists were able to block MID expression in genetic males causing them to develop with functional eggs in place of their sperm packets. The team was even able to use their gender-swapped strains to carry out successful matings between pairs of genetically male or genetically female Volvox. Importantly, even though the MID genes from the two species of algae are related, the Chlamydomonas MID gene was unable to substitute for Volvox MID. The discovery of a master regulatory gene for sexes and mating types in this group of green algae shows that these two forms of reproduction share a common genetic origin, and hint that a similar evolutionary scenario may underlie the origin of sexes in animals, plants and other multicellular lineages.

In addition to the evolutionary insights gained by Umen's research team, there are also practical implications for algal biotechnology. "Just as is the case for crop plants, breeding will be an important tool for making improved algal strains that can serve as biofuel feed stocks or other purposes. However, sexual reproduction in most algal species is poorly understood. The identification of a conserved regulatory gene that controls sex and mating in the algae may lead to clues about how sex is controlled in other related groups of algae that are used for biotechnological applications," Umen said.


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. Sa Geng, Peter De Hoff, James G. Umen. Evolution of Sexes from an Ancestral Mating-Type Specification Pathway. PLoS Biology, 2014; 12 (7): e1001904 DOI: 10.1371/journal.pbio.1001904

Cite This Page:

Public Library of Science. "Transgender algae reveal evolutionary origin of sexes." ScienceDaily. ScienceDaily, 8 July 2014. <www.sciencedaily.com/releases/2014/07/140708153900.htm>.
Public Library of Science. (2014, July 8). Transgender algae reveal evolutionary origin of sexes. ScienceDaily. Retrieved July 21, 2014 from www.sciencedaily.com/releases/2014/07/140708153900.htm
Public Library of Science. "Transgender algae reveal evolutionary origin of sexes." ScienceDaily. www.sciencedaily.com/releases/2014/07/140708153900.htm (accessed July 21, 2014).

Share This




More Plants & Animals News

Monday, July 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

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
A Centuries' Old British Tradition Is Far from a Swan Song

A Centuries' Old British Tradition Is Far from a Swan Song

AFP (July 19, 2014) As if it weren't enough that the Queen is the Sovereign of the UK and 15 other Commonwealth realms, she is also the owner of all Britain's unmarked swans. Duration: 02:18 Video provided by AFP
Powered by NewsLook.com
Tooth Plaque Provides Insight Into Diets Of Ancient People

Tooth Plaque Provides Insight Into Diets Of Ancient People

Newsy (July 19, 2014) Research on plaque from ancient teeth shows that our prehistoric ancestor's had a detailed understanding of plants long before developing agriculture. 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