New techniques for gene sequencing

Next generation techniques have decoded the genome of the fungus Sordaria macrospora with some surprising results.

Researchers from the Ruhr-Universität discovered that the fungus contained multiple copies of the same genes – a factor which often causes cell death in other fungi due to immune-like reactions. They also found genes from distant relatives, suggesting horizontal gene transfer during evolution.

Using high-throughput methods, a team of researchers led by Professor Dr Ulrich Kück sequenced nearly 100 million individual sections of DNA. Their technique reads between 36 and 450 base pairs – the traditional Sanger method reads a maximum of 1,000 – which are pieced together using newly developed programs on powerful computers.

“Fungal genomes are about 100 times smaller than the human genome – 40 million base pairs in the genome of Sordaria macrospora, 3,000 million in the human genome,” explained Professor Kück, “They still encode a similarly large number of genes: approximately 11,000 genes in Sordaria macrospora, about 25,000 in humans.”

The researchers discovered that the fungus genome contains multiple copies of genes – in other fungi these genes distinguish between “self” and “non-self”, similar to the way the body distinguishes between foreign tissues in medical transplants. Unlike other fungi, Sordaria macrospora is able to cope with these multiple copies – how it is able to do this remains unclear.

It was also discovered that the fungus have ‘taken over’ several genes from other distantly related fungus by means of horizontal gene transfer during the course of evolution. This expands the biochemical abilities of the fungus.

The new high-throughput techniques can be used to sequence the genomes of complex organisms at a low cost compared to traditional methods.