Complex sentence: To this end they are studying the variation in the human genome and have led an international effort which has assembled a library of 2.1 million single-nucleotide polymorphisms (SNP) these act as markers or signposts in the genome allowing the identification of disease susceptibility genes.
Split into simpler sentences: To this end they are studying the variation in the human genome and have led an international effort which has assembled a library of 2.1 million single-nucleotide polymorphisms (SNP). These act as markers or signposts in the genome allowing the identification of disease susceptibility genes.