Two teams of investigators led by Professor Gregory Hannon of Cold Spring Harbor Laboratory (CSHL) today publish studies revealing many previously unknown components of an innate system that defends sex cells – the carriers of inheritance across generations – from the ravages of transposable genetic elements.
When activated, these troublesome segments of DNA, also called jumping genes or transposons, can copy and insert themselves at random spots across the chromosomes. In sperm and egg cells the proliferation of transposons can be particularly devastating, causing severe developmental impairments in offspring as well as sterility. Over the eons of evolution, complex organisms have developed means of defending their germline genomes against transposons, principally via a series of mechanisms that scientists call the piRNA pathway.