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A new finding could lead to genetic engineering and gene therapy technologies improvements, scientists have said.
US researchers found a molecular “security system” in cells that neutralises and removes potentially harmful foreign DNA.
They found an enzyme in human immune cells that disables double-stranded foreign DNA by altering one of its chemical elements.
APOBEC3A transformed cytosine, one of the four main “bases” in DNA making up the genetic code, into a rarer form called uracil.
Persisting uracils make unwanted foreign DNA molecules safely inactive by eventually disabling DNA, and other enzymes degrade the uracil-neutralised DNA and sweep its remains out of the cell.
Foreign DNA can infiltrate the genetic code, or genome, leading to malfunctions and disease and could be permanently embedded and passed on to offspring.
DNA in pigs is derived from the endogenous porcine retrovirus, which some experts fear could be passed on to humans through transplant organs grown in the animals.
A new study suggests that up to 8% of human DNA may originally have been imported from a virus and could play a role in mental illnesses such as schizophrenia.
Copyright Press Association 2010
