There are some creatures that endear their way into people's hearts. Cockroaches are not one of them.

The brown and round insects are notorious for living in inhospitable places and being difficult to get rid of. Now, scientists know a little bit more about just what makes them so hardy.

Researchers from the South China Normal University have sequenced their DNA, drilling down to the insects' essential building blocks. Their findings were published in the journal Nature Communications.

The researchers began by sequencing the DNA of several species of cockroach and found that American cockroaches, Periplaneta americana, have one of the largest known genome sequences of all insects, second only to locusts.

The DNA of Australian cockroaches and smokybrown cockroaches were also sequenced,