Anolis carolinensis , more commonly called the Carolina Anole lizard, is an unusual reptile that actually evolved from the same common ancestor as mammals about 320 million years ago.
However unlikely it may seem, Dr. Matthew Breen thinks that the lizard potentially carries important information about the human genome. To uncover this relationship, he looks for regions of shared synteny —genes located along the same chromosome—between the lizard genes and those of humans and dogs.
“Most reptiles have their sex determined by environmental factors such as temperature,” Breen said. “With mammals, on the other hand, sex is determined by X and Y chromosomes, with females having two X chromosomes and males having one of X and Y. We found these lizards having mammalian type sex determination, with the females having two copies of X chromosomes and males having one.”
Dr. David Threadgill , head of the Genetics Department, believes studying the genomes of other species can lead to an understanding of how human genomes evolve over time.
“In fact, one of the main benefits of studying the lizard genome is that it can provide insight into human reproduction and on how the transition from eggs to live births took place for mammals,” Threadgill said.
Breen said his primary research goal is to determine the link between the study of evolution and a cure for cancer.
“People might think I am crazy, but I believe both of them are the same thing,” Breen said. “Cancer is just evolution taking place at a massively accelerated rate. The difference is that evolution takes millions of years, hence giving creatures the time to adapt. Since the changes caused by cancer are so fast and often quite extensive, the cell does not have time to adapt.”
According to Threadgill , this work in genomics could shed light on the processes of cell division caused by cancer, including how control mechanisms for cells come into place, and what can be done when things do not work correctly.
Breen said the genetic mutations caused by cancer are very similar in all animals and humans, so knowledge about mutations in any species greatly helps in study of another.
“The greatest part of all this knowledge is that it is able to be used comparatively—what is known about one species or animal group can be applied to many others without the need for starting at square one all over again,” Christina Williams, a research associate of Breen’s , said.
Genomics itself has come a long way, according to Breen , from the time he initially started his work in the human genome project, which was then in its nascent stages.
“It took almost 15 years and several billion dollars to sequence the first human genome, but as technology has advanced, genome sequencing has accelerated and reduced in cost,” Breen said. “[Sequencing] the dog genome took about a year and cost around $ 50M , while the horse took about six months and cost about $15 million.
According to Breen , sequencing genomes now takes as little as a few weeks.
“Now, we have some companies to whom you can send your spit in a cup and they will e-mail you back your chances of risk for diseases, using aspects of your gene sequencing,” Breen said.
By the end of 2012, Breen predicts that companies will be able to sequence totally new genomes in a few hours for less than a thousand dollars.
His analogy is to view the genome as a book. The approach they use, called shotgun cloning, is equivalent to putting the book into a shredder, shearing it into billions of pieces and then re-assembling it.
This is much faster than the conventional approach used in earlier days, which was to go through the whole genome word by word, then page by page. At this rate, the human genome alone would have taken 25 years to finish.
The re-assembly of sequenced DNA remains the tricky part, as it requires massive computing power and sequencing capacity.
After this lizard, Breen will focus his attention to the alligator genome.
