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 ")
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.
Tsunami Forecasts Improved By Ionosphere Signals
'Swifter than any tide could ebb, the water was receding from the shore.'
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
JAXA Int Ball 2 Coming Right Along As Star Wars Remote
'Hocus-pocus religions and archaic weapons are no substitute for a good blaster at your side.'
Robot Bricklayer Or Passer-By Bricklayer?
'Oscar picked up a trowel. 'I'm the tool for the mortar,' the little trowel squeaked cheerfully.'
Robot Gas Station Attendant Pumps Gas For You
'... he waited for the robotrix attendant to finish fueling up his ship.'
Engineer Creates Crazy Motorized Track Hospital Bed
The Roujin Z system provides care to fully bedridden patients - and then some!
Tiny Flying Robot Weighs Just One Gram
'Aerostat meant anything that hung in the air. This was an easy trick to pull off nowadays.'
Some Ringworld Configurations Are Stable
'The Ringworld had no horizon. There was no line where the land curved away from the sky.'
TRANSFORM Dynamic Furniture Concept Becomes What You Need
'An adjustment panel outside the door would cause it to extrude various appurtenances in memory plastic...'
Harvard Metamaterials Change Structure Instantly
'Annealed in any shape for a time, and codified, the structure of that shape is retained down to the molecules.'
SnapBot Robots - You Choose Their Legs And They Choose Their Gaits
It's not really polite to tear the limbs off robots.
Dino From Magical Toys An AI Companion To Children
'...the imaginary companions discovered by needful children.'
Humanoid Robots Building Humanoid Robots
''Pardon me, Struthers,' he broke in suddenly... 'haven't you a section of the factory where only robot labor is employed?''
Darpa 'Defiant' Unmanned Autonomous Ship
'There was no wheel, and no steersman!'
What's The Best Way To Ship And Unpack Humanoid Robots?
'I opened the oblong box, where lay the automatons side by side...'
DNA Printed Book By Isaac Asimov Now Available
'They tied the memory to the bloodline and that was their record!'
AI Computer Chip Designs Passeth Human Understanding
'It seems that at one time computers were designed directly by human beings.'
Space Traffic Management (STM) Needed Now
'...the spot was a lonely one in an uncharted region, far from the normal lanes of space traffic.'
