Featured Research

from universities, journals, and other organizations

'Third gender' identified in close relative of olive tree

Date:
April 1, 2010
Source:
CNRS
Summary:
A hitherto unknown reproductive system in a species closely related to the olive tree, Phillyrea angustifolia L., has been discovered. This new reproductive mode explains the mystery of the high frequencies (up to 50%) of male individuals co-occurring with hermaphrodite individuals in this species.

A hitherto unknown reproductive system in a species closely related to the olive tree, Phillyrea angustifolia L., has been discovered by researchers in France.

This system explains the high concentration of male individuals co-occurring with hermaphrodites in this species. The hermaphrodites, whose blossoms bear both male and female organs, are divided into two morphologically indistinguishable groups. The plants of each group are sterile among themselves but fully compatible with those of the other group. Under these conditions, the hermaphrodites can fertilize only half of the pollen recipients, whereas the males can pollinate all the hermaphrodites. The disadvantage weighing upon the males is thus neatly counterbalanced. This discovery proves for the first time the possibility of an evolutionary transition from hermaphroditism to dioecy.

A report has been published in Science.

Researchers at the Laboratoire de Génétique et Évolution des Populations Végétales (CNRS/Université de Lille 1) and the Centre d'Écologie Fonctionnelle et Évolutive (CNRS/Université de Montpellier 1, 2 and 3/ENSA Montpellier/CIRAD/Ecole Pratique des Hautes Études) have discovered in Phillyrea angustifolia L., a species closely related to the olive tree, a hitherto unknown reproductive system characterized by incompatibility between hermaphrodite plants.

This new reproductive mode explains the mystery of the high frequencies (up to 50%) of male individuals co-occurring with hermaphrodite individuals in this species. The hermaphrodite individuals, whose blossoms bear both male and female organs, are divided into two morphologically indistinguishable groups. The plants of each group are self-incompatible (they cannot fertilize each other) but fully compatible with plants of the other group. In such a system, a given hermaphrodite plant can pollinate only half of the other hermaphrodites, while a male can pollinate all the hermaphrodites in the population. These conditions neatly offset the reproductive disadvantage affecting the males, which have no female function (and are also referred to as "female-sterile" for this reason) and can thus transmit their genes only by male gametes, and not by both male and female gametes like the hermaphrodites.

In addition, this self-incompatibility within two morphologically identical groups of hermaphrodites could be a key reproductive mode, the origin of plant species with separate genders that evolve through "intermediary" reproductive systems. In the overall context of the evolution of reproductive systems from hermaphroditism toward dioecy (system in which individuals are exclusively either male or female), mixed systems involving the presence in the same species of both females and hermaphrodites (gynodioecy) or both males and hermaphrodites (androdioecy) are considered intermediaries derived from hermaphroditism. However, all previous empirical examples have shown that androdioecy had evolved from dioecious systems through the females' acquisition of a male function, and not from hermaphroditic systems through the loss of the female function by certain hermaphrodites. This new study shows for the first time that a transition from hermaphroditism to androdioecy (presence of hermaphrodite and male individuals within the populations of a single species) is possible.

This discovery of a self-incompatibility system involving only two morphologically indistinguishable groups of hermaphrodite plants comes as a totally unexpected development. One of the researchers' next challenges will be to explain, from a functional point of view, how the number of self-incompatibility groups has been maintained at two.


Story Source:

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


Journal Reference:

  1. P. Saumitou-Laprade, P. Vernet, C. Vassiliadis, Y. Hoareau, G. Magny (de), B. Dommee, J. Lepart. A Self-Incompatibility System Explains High Male Frequencies in an Androdioecious Plant. Science, 26 March 2010 DOI: 10.1126/science.1186687

Cite This Page:

CNRS. "'Third gender' identified in close relative of olive tree." ScienceDaily. ScienceDaily, 1 April 2010. <www.sciencedaily.com/releases/2010/03/100331141614.htm>.
CNRS. (2010, April 1). 'Third gender' identified in close relative of olive tree. ScienceDaily. Retrieved August 21, 2014 from www.sciencedaily.com/releases/2010/03/100331141614.htm
CNRS. "'Third gender' identified in close relative of olive tree." ScienceDaily. www.sciencedaily.com/releases/2010/03/100331141614.htm (accessed August 21, 2014).

Share This




More Plants & Animals News

Thursday, August 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Newsy (Aug. 21, 2014) — An experimental drug used to treat Marburg virus in rhesus monkeys could give new insight into a similar treatment for Ebola. Video provided by Newsy
Powered by NewsLook.com
Terrifying City-Dwelling Spiders Are Bigger And More Fertile

Terrifying City-Dwelling Spiders Are Bigger And More Fertile

Newsy (Aug. 21, 2014) — According to a new study, spiders that live in cities are bigger, fatter and multiply faster. Video provided by Newsy
Powered by NewsLook.com
California Drought Stings Honeybees, Beekeepers

California Drought Stings Honeybees, Beekeepers

AP (Aug. 21, 2014) — California's record drought is hurting honey supplies and raising prices for consumers. The lack of rainfall means fewer crops and wildflowers that provide the nectar bees need to make honey. (Aug. 21) Video provided by AP
Powered by NewsLook.com
Possible Ebola Patient in Isolation at California Hospital

Possible Ebola Patient in Isolation at California Hospital

Reuters - US Online Video (Aug. 20, 2014) — A patient who may have been exposed to the Ebola virus is in isolation at the Kaiser Permanente South Sacramento Medical Center. Linda So reports. Video provided by Reuters
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