Science Fiction
Dictionary
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
 |
This Species Has Seven Sexes
The single-celled organism Tetrahymena thermophila has seven sexes, not just two, which you would think would improve your odds tremendously.
(Young healthy VII WLTM I, II, III, IV, V, VI for conjugation
Image: Volker Steger/E. Cole/SPL)
Tetrahymena thermophila is a single cell covered with a coat of hairs called cilia. The cilia wave back and forth, powering it through the water.Its seven sexes are rather prosaically named I, II, III, IV, V, VI and VII. An individual of a given sex can mate with individuals of any except its own, so there are 21 possible orientations.
In most animals, what sex you are is straightforward. A human with two X chromosomes is female, while someone with an X and a Y is male...
Not so for Tetrahymena. Its sex is controlled by a gene called mat, but it is not as simple as one version of the gene encoding one sex. Instead, each allele of the gene sets out a series of probabilities. For instance, an individual born with the mat2 allele has zero chance of being type I, a 0.15 chance of being type II, a 0.09 chance of being type II, and so on.
There are at least 14 of these alleles, each offering a different set of probabilities...
Although not a prediction, sf writers often explore unusual, well, circumstances. In his sardonic 1949 story Venus and the Seven Sexes, writer William Tenn tells us about a rather complicated arrangement - the seven sexes of the Plookh.
"...I am a representative of the seventh sex - nzred.""A nzred, huh? What do you do?"
"I coordinate... You see, a mlenb is primarily interested in winning the affections of a likely strob and finding a tkan whom he can love. A tkan merely courts a mlenb and is attracted to a good guur. I am responsible for getting a complete chain of these individuals in operation, a chain of compatibility where perfect amity runs in a complete circle - a chain which will produce offspring of maximum variability. Then, after the matrimonial convention, when the chain is established, each sex begins to secrete in its original germ with the full forty-nine chromosomes. A busy time for the nzredd!
"The nzred... fits himself in at any point in the chain which the exigencies of the situation seem to demand. He may receive the sextuple supergamete from the tkan and transmit the original single gamete to the guur, he may be between the flin and blap, the blap and srob, whatever is required."
Via NewScientist.
Scroll down for more stories in the same category. (Story submitted 3/16/2011)
Follow this kind of news @Technovelgy.| Email | RSS | Blog It | Stumble | del.icio.us | Digg | Reddit |
Would
you like to contribute a story tip?
It's easy:
Get the URL of the story, and the related sf author, and add
it here.
Comment/Join discussion ( 3 )
Related News Stories - (" Biology ")
Black Fungus Blocks Radiation
'You were surrounded by Astrophage most of the time' - Andy Weir, 2021.
Lunar Biorepository Proposed For Cryo-Preservation Of Earth Species
'...there was no one alive who had ever seen them. But they existed in the Life Bank.' - John Varley, 1977.
Let's Make Slaver Sunflowers! Engineering Plants To Reflect Light
'The mirror-blossom was a terrible weapon.' - Larry Niven, 1965.
Machete-Wielding Philodendron Isn't Going To Take It Anymore
'The tree ended its wild larruping, stood like a dreaming giant liable to wake into frenzy at any moment.' - Eric Frank Russell, 1943.
Technovelgy (that's tech-novel-gee!) is devoted to the creative science inventions and ideas of sf authors. Look for the Invention Category that interests you, the Glossary, the Invention Timeline, or see what's New.
Science Fiction
Timeline
1600-1899
1900-1939
1940's 1950's
1960's 1970's
1980's 1990's
2000's 2010's
Current News
The New Habitable Zones Include Asimov's Ribbon Worlds
'...there's a narrow belt where the climate is moderate.'
Atlas Robot Makes Uncomfortable Movements
'Not like me. A T-1000, advanced prototype. A mimetic poly-alloy. Liquid metal.'
Boring Company Drills Asimov's Single Vehicle Tunnels
'It was riddled with holes that were the mouths of tunnels.'
Humanoid Robots Tickle The Ivories
'The massive feet working the pedals, arms and hands flashing and glinting...'
A Remarkable Coincidence
'There is a philosophical problem of some difficulty here...'
Cortex 1 - Today A Warehouse, Tomorrow A Calculator Planet
'There were cubic miles of it, and it glistened like a silvery Christmas tree...'
Perching Ambush Drones
'On the chest of drawers something was perched.'
Leader-Follower Autonomous Vehicle Technology
'Jason had been guiding the caravan of cars as usual...'
Golf Ball Test Robot Wears Them Out
"The robot solemnly hit a ball against the wall, picked it up and teed it, hit it again, over and again...'
Boring Company Vegas Loop Like Asimov Said
'There was a wall ahead... It was riddled with holes that were the mouths of tunnels.'
Rigid Metallic Clothing From Science Fiction To You
'...support the interior human structure against Jupiter’s pull.'
Is The Seattle Ultrasonics C-200 A Heinlein Vibroblade?
'It ain't a vibroblade. It's steel. Messy.'
Roborock Saros Z70 Is A Robot Vacuum With An Arm
'Anything larger than a BB shot it picked up and placed in a tray...'
A Beautiful Visualization Of Compact Food
'The German chemists have discovered how to supply the needed elements in compact, undiluted form...'
Bone-Building Drug Evenity Approved
'Compounds devised by the biochemists for the rapid building of bone...'
Secret Kill Switch Found In Yutong Buses
'The car faltered as the external command came to brake...'
