New animal family tree places us closer to weird diskshaped organisms

News Summary

  • It turns out that individual genes tend to stay in the same place on a chromosome for long periods of time; it's estimated that it takes 40 million years for just one percent of the genes in a typical animal genome to move to a new chromosome.
  • Again, they performed 100 million random simulations and never saw this pattern of inheritance, so it seems to be real.This means that animals like us vertebrates, along with everything else that has a left and right side, is more closely related to sponges than we are to comb jellies.
  • So, the exact answer you get can sometimes depend on what genes you choose to look at.The new study tries to avoid the confusion by looking at how genes are arranged on chromosomes.
  • The researchers were only able to identify a bit under 300 genes that were in clusters that extended back to the single-celled relatives of animals, with the biggest cluster including 29 genes.
  • And, by tracking changes in the arrangement of genes across different species, we can figure out where in an organism's past groups of genes got broken up, and which other species inherited the same rearrangement.
  • But these barely scratch the surface of animal diversity, with things like cephalopods, insects, and echinoderms all having distinct features.And that's before you get to the really weird stuff, like the radially symmetric Cnidarians, or the sponges that lack muscle and nerve cells.
Enlarge/ These complex creatures seem to be the earliest branch of the animal tree. Were more closely related to sponges than we are to them.2 with Ask someone to think of an animal, and chances [+5178 chars]