Say Cheeeeese!!! February 24, 2010Posted by ecogeeko10 in Biology, Genetics.
So I’ve been noticing a recent trend in the scientific world lately. Researchers are getting better and better at figuring out the fine details of organisms that occurred many years ago. Take dinosaurs for, for example. It was once thought that all of these “terrible lizards” were only covered with scales. However, it wasn’t too long ago when paleontologists first began finding evidence that some species of dinosaurs actually had feathers. Not many people believed that we would ever get to figure out the actual colors of these feathers, but it turns out that this is also possible.
Jakob Vinther, a graduate student at Yale University was studying the ink sac of an ancient squid, when he discovered microscopic melanosomes in the fossil. Melanosomes are cellular organelles that contain melanin, which is a light-absorbing pigment that is found in certain animals such as birds. Once researchers heard about this discovery, they quickly began examining the fossil remains of other organisms such as Anchiornis huxleyi. We can now conclude that many dinosaurs like A. huxleyi were not necessarily dull and gray, but rather, they were quite colorful (see figure 1). The fact that this species of dinosaurs was so colorful could prove that feathers may have had multiple adaptive uses at that time. Not only were they good for warmth and flight (eventually), but they were instrumental display features. What dinosaur wouldn’t want to mate with such a beautifully adorned creature? This was a very important discovery because it gives evolutionary biologists much more insight into the evolution of birds. We now have more evidence that birds did indeed evolve from theropod dinosaurs.
But wait!!! I’m not done!!!
It also turns out that we are able to take “snap-shots” of people who lived thousands of years ago! Just recently researchers were able to analyze the complete genome of a 4,000 year old Greenland resident—a Saqqaq. Simply by analyzing the DNA in this old man’s hair, geneticists were able to conclude that this man had brown eyes, dry ear wax, was genetically prone to have thicker hair (thicker than most Europeans and Africans), and yet he was also at risk of growing bald (see figure 2 for “snap-shot”).
What’s most important about this discovery, though, is that these findings help to shed new light on the settlement of North America. Apparently, through analyzing this man’s genome, researchers were able to determine that his closest living relatives were the Chukchis—who lived on the easternmost tip of Siberia. What’s interesting is that the Saqqaq man’s ancestors diverged from the Chukchis around 5,500 years ago and that helps geneticists to believe that this man’s ancestors must have traveled across the northern edges of North America to Greenland.