Wednesday, March 23, 2005
Meddling With Mendel
Biologists at Purdue University have found a plant that defies the 150-year old Mendelian inheritance laws and contradicts some of the most fundamental tenets of genetics.
The plant in question was able fix a mutant gene passed on by both parents. It simply skipped a generation and reverted to a healthy state of its grandparents. "This means that inheritance can happen more flexibly than we thought in the past," said Robert Pruitt, a molecular geneticist at Purdue. "While Mendel's laws that we learned in high school still are fundamentally correct, they're not absolute."
The scientists kept the plants, called Arabidopsis, in isolation so they couldn't accidentally crossbreed with plants that didn't have the mutated gene. Pruitt said that Arabidopsis have somehow kept a "cryptic copy of everything that was in the previous generation, even though it doesn't show up in the DNA, it's not in the chromosome. Some other type of gene sequence information that we don't really understand yet is modifying the inherited traits."
There's already talk that DNA may not be the only carrier of genetic information and the driver of evolution. Scientists have proposed that genes may be also passed by the less stable strands of DNA's cousin, RNA.
The plant in question was able fix a mutant gene passed on by both parents. It simply skipped a generation and reverted to a healthy state of its grandparents. "This means that inheritance can happen more flexibly than we thought in the past," said Robert Pruitt, a molecular geneticist at Purdue. "While Mendel's laws that we learned in high school still are fundamentally correct, they're not absolute."
The scientists kept the plants, called Arabidopsis, in isolation so they couldn't accidentally crossbreed with plants that didn't have the mutated gene. Pruitt said that Arabidopsis have somehow kept a "cryptic copy of everything that was in the previous generation, even though it doesn't show up in the DNA, it's not in the chromosome. Some other type of gene sequence information that we don't really understand yet is modifying the inherited traits."
There's already talk that DNA may not be the only carrier of genetic information and the driver of evolution. Scientists have proposed that genes may be also passed by the less stable strands of DNA's cousin, RNA.
