4 ms·

How a Tiny Chunk of DNA Can Keep Two Species Apart

21 points by digital55 12y ago

Strilanc 12y ago
> Genome analysis suggests that the two species are swapping genes at a surprising rate. But each species has genome segments unique to its own kind, which seem to persist despite the mixing of the rest of the genome. If the population was split and bottlenecked and recombined, would you get a lot of this sort of "either AAAAAAAAAAAAAAAAAAA or BBBBBBBBBBBBBBBBB" correlated variation? Maybe we're just seeing a point before crossover undoes that effect? (On the other hand, the researchers would probably have noticed the lack of genetic variety if all these cases had gone through bottlenecks.)
- a_bonobo 12y ago
  Recombination doesn't happen everywhere with the same probability. Brassica napus, for example, seems to actively suppress (somehow) recombination between homeologous chromosomes (chromosomes that came from the same ancestor chromosome) to make sure that reproduction runs flawlessly: http://www.plantcell.org/content/22/7/2265.full http://www.plantcell.org/content/22/7/2265.full In most species recombinations are suppressed around centromeres: http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1000326 http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjo... Sometimes there are specialized proteins involved undoing or blocking crossovers, sometimes it just seems to be a mechanical problem - for example, you can't have crossovers happening close to other crossovers because the machinery is so large that a secondary set of chromosomes can't dock for a distance of few thousand base pairs.
mentos 12y ago
Well "only mate with a bird of a similar color" seems like a hard problem that is wrapped up in 1.2 billion lines of DNA code/evolution. The 82 letters of DNA that separate them may just be their color codes?
- keeperofdakeys 12y ago
  Can the bird see their own colour? Are they just attracted to the colour that their parents are? Are those 82 letters 'keys' designed to make other parts of DNA form different cells? There are a few too many questions to really answer fully.
heroku 12y ago
I am confused, I thought everybody had different dna's, or is it not?

21 points by digital55 12y ago

> Genome analysis suggests that the two species are swapping genes at a surprising rate. But each species has genome segments unique to its own kind, which seem to persist despite the mixing of the rest of the genome. If the population was split and bottlenecked and recombined, would you get a lot of this sort of "either AAAAAAAAAAAAAAAAAAA or BBBBBBBBBBBBBBBBB" correlated variation? Maybe we're just seeing a point before crossover undoes that effect? (On the other hand, the researchers would probably have noticed the lack of genetic variety if all these cases had gone through bottlenecks.)

a_bonobo 12y ago
Recombination doesn't happen everywhere with the same probability. Brassica napus, for example, seems to actively suppress (somehow) recombination between homeologous chromosomes (chromosomes that came from the same ancestor chromosome) to make sure that reproduction runs flawlessly: http://www.plantcell.org/content/22/7/2265.full http://www.plantcell.org/content/22/7/2265.full In most species recombinations are suppressed around centromeres: http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1000326 http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjo... Sometimes there are specialized proteins involved undoing or blocking crossovers, sometimes it just seems to be a mechanical problem - for example, you can't have crossovers happening close to other crossovers because the machinery is so large that a secondary set of chromosomes can't dock for a distance of few thousand base pairs.

mentos 12y ago

Well "only mate with a bird of a similar color" seems like a hard problem that is wrapped up in 1.2 billion lines of DNA code/evolution. The 82 letters of DNA that separate them may just be their color codes?

keeperofdakeys 12y ago
Can the bird see their own colour? Are they just attracted to the colour that their parents are? Are those 82 letters 'keys' designed to make other parts of DNA form different cells? There are a few too many questions to really answer fully.

heroku 12y ago

I am confused, I thought everybody had different dna's, or is it not?