How did this come about? Understanding the population structure of T. gondii helps us understand how it acquires and spreads the various elements that enable it to cause disease, so the authors of a paper in mBio this week looked closely at the genome of T. gondii isolates to try and figure it out.
They found that Chrla is very similar in North America/Europe and in South America, which suggests that the chromosome has been transferred recently between the diverse T. gondii populations in South America and into the T. gondii that subsequently expanded clonally in North America and Europe. The fact that Chrla is very similar in both South America, where T. gondii propagates sexually, and in North America/Europe, where it propagates asexually, suggests that it confers a selective advantage no matter how the parasite propagates.
