Shuffling Through Seven Sexes

Researchers show that random rearrangement of DNA determines which of seven possible mating types the offspring of a single-celled microbe will be.

By | March 28, 2013

Tetrahymena thermophilaWIKIMEDIA, R ROBINSONWhen the protozoan Tetrahymena thermophila mates, its offspring can end up as any one of seven different mating types. Their fate is determined not by the mating types of the parents, but by a process of random genome rearrangement in which segments of DNA from the mating pair are whittled down until one of seven possible genes remains in the offspring, according to a study published this week (March 27) in PLOS Biology.

It was previously known that the mating type of the T. thermophila parents had no bearing on that of the offspring. To find out why, a team of biologists including Eduardo Orias of the University of California, Santa Barbara, took a closer look at the genetic mechanisms involved. T. thermophila have two nuclei: the somatic nucleus, which holds a genome that governs its own mating type, and the germline nucleus, which contains the genetic information that will be passed down to its offspring.

The genome in this germline nucleus contains incomplete genes for all seven mating types. The researchers found that these are combined with the mate’s collection of incomplete genes and passed to the newly formed somatic nucleus of the offspring. There, the DNA is shuffled and bits are deleted at random until there are only enough segments to make one complete gene, which determines the offspring’s mating type.

“You’re removing a link out of the system until you get down to the last link and you cannot remove any more,” Orias told Nature.

Add a Comment

Avatar of: You



Sign In with your LabX Media Group Passport to leave a comment

Not a member? Register Now!

LabX Media Group Passport Logo

Popular Now

  1. Running on Empty
    Features Running on Empty

    Regularly taking breaks from eating—for hours or days—can trigger changes both expected, such as in metabolic dynamics and inflammation, and surprising, as in immune system function and cancer progression.

  2. Athletes’ Microbiomes Differ from Nonathletes
  3. Gut Feeling
    Daily News Gut Feeling

    Sensory cells of the mouse intestine let the brain know if certain compounds are present by speaking directly to gut neurons via serotonin.

  4. Immune Cells Deliver Cancer Drugs to the Brain