http://www.sciencedaily.com/releases/2009/04/090412081315.ht
A new study has found that DNA isn’t everything when determining certain physical characteristics. Research into "epigenetics"(the study of factors that change Characteristics other than DNA...such as the Environment) has shown that environmental factors affect characteristics of organisms. These changes are sometimes passed on to the offspring. Renato Paro (an ETH professor) does not believe that this opposes Darwin’s theory of evolution, while others do.
"A certain laboratory strain of the fruit fly Drosophila melanogaster has white eyes. If the surrounding temperature of the fly embryos, (which is normally nurtured at 25 degrees Celsius) is raised to 37 degrees Celsius, the flies later hatch with red eyes. If these flies are again crossed, the following generations are partly red-eyed – without further temperature treatment – even though only white-eyed flies are expected according to the rules of genetics." - Professor Renato Paro
Researchers in a group led by the professor for "Biosystems at the Department of Biosystems Science and Engineering (D-BSSE)" crossed breaded flies of six generations. With this experiment they were able to determine that temperature treatment changes the eye color of this specific strain of fly, as well as treat individual flies so they pass on the changes to their offspring over several generations. Scientists have been able to alter DNA to affect the outcome of eye color to be other than what they inherit genetically from their parents for quite some time now, so this in and of it’s self is not as important. What makes this discovery groundbreaking is twofold; 1) the eye color of the flies was changed by different temperatures in the environment surrounding the embryos. 2) After the eye color was changed and then cross-breaded, in comparison to samples of DNA taken before the change in temp and therefore Eye color the DNA strand responsible for eye color remained completely unchanged.
If it's still a little confusing think of it like this: The DNA sequence for the gene responsible for eye color was proven to remain the same for white-eyed parents and red-eyed offspring.
However, what still remains a mystery to scientists is 1) how eye color of a fly can be changed by natural means (Temperature), 2) how the gene responsible for determining eye color can remain unchanged while the eye color does change, 3) as well as how its possible for the change to occur without effecting DNA and yet it's passed onto their offspring. To help explain what makes this unique, hypothetically it’s like if mother who is in the beginning stages of pregnancy got a cut on her arm that left a scar then her child was born with the same exact scar on his/her own arm. The scar does not affect the DNA sequence, and children inherit their characteristics via DNA, So the question remains how is it possible for a characteristic to be passed on from parent to offspring if its not written into the DNA sequence while the characteristic changes, but the DNA strand that determines if it changes remains the same without alteration
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