In light of Charles Darwin’s birthday a study that
identified the gene that controls beak size in the Galapagos finches was published
on February 11, 2015, just one day before Darwin’s birthday. The study, which
was undertaken by researchers at Princeton University and Uppsala University, highlights
the genetic aspects of evolution as well as gene flow and speciation. More specifically,
it was discovered that evolution occurs in halting and disordered steps, allowing
for genes to spread and create new lineages. Eventually the new lineages can
evolve into entirely new species given the right set of circumstances.
DNA samples from 120 birds were collected and the genomes of
the birds were studied. Each of Darwin’s 15 species of finches was represented
in the population of the 120 birds. After studying the genomes the researchers
noted a stretch of DNA that was different in finches with blunt beaks and in
finches that had sharp, pointed beaks. A gene, ALX1, was found within that
section of DNA. In humans and mice this gene influences the development of
facial features. If this gene mutates and becomes inactivated then severe
abnormalities in humans can result. However, mild mutations of this gene have
the opposite effect in the finches. Instead these mutations lead to observable
evolution in the finches. It was also found that individual birds of the same
species sometimes had different forms of the gene. Of course, this finding is
huge as natural selection runs off of genetic variation and cannot occur
without it and natural selection is a means through which evolution happens.
Having studied the finches for forty years the researchers
on this study know that the size and shape of the finches’ beaks plays an
immense role in their survival, just as Darwin did. They realized that the tough environment that these
birds are exposed to made it essential that the finches had appropriate beaks
that were suited to their habitat. However, until this study was conducted the
researchers did not understand the genetic aspect of the evolution of these
finches.
Along with locating the gene that plays a role in the
evolution of these finches the study also provides more information about what
happens when genes are passed from one species to another (between two closely
related species). Usually, the offspring of these two closely related
individuals would be sterile, but that is not the case with the finches. The
offspring can mate with individuals from either of the two parental species. The
baby finch will conform to one of the parental species based on song and appearance.
However, the finch still contains genes from both parents. This process, known
as gene flow, has given the researchers a better picture of how genes move from
specie to specie and create new species.
I think that this is really interesting and I haven’t thought
much about it. It never really occurred to me that all of Darwin’s work was
observed and he of course had no idea what genes were and which genes were playing
a role in evolution. It is surprising to me that it has taken researchers so
long to discover this about the finches, but it was nice that they published
the study near his birthday. Honestly, I didn't think anyone still cared about
the finches and didn't know that they were still being researched. It just
shows that the Galapagos Islands offer many interesting species to study and
that even though evolution has been studied so much there is still so much to
learn.
Link to Article: http://www.sciencedaily.com/releases/2015/02/150211153923.htm
Additional Links: http://beforeitsnews.com/science-and-technology/2012/08/scientists-sequence-genome-of-darwins-finch-2455302.html
I have personally read On the Origin of Species and based on the technology we have today, Darwin was living in the stone age. He was very smart and he was able to see these correlations and infer better than a lot of people can nowadays despite the technology and further research. I will never for the life of me understand people who don't see any credibility in evolution because without it, we'd all still be little single-celled organisms swimming around somewhere.
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