Scientists have sequenced the entire genome of the common housefly and claim that their findings must aid in unveiling latest cures for various human diseases. The fly has the potential to carry around 100 illnesses, including blindness as well
By comparing its DNA with that of a fruit fly, the US team at Cornell University pinpointed the genes that makes houseflies immune to the pathogens they harbour.
They also found unique code that helps the fly dissolve waste, such as faeces. Information about these genes could help us to handle human waste and improve the environment, Dr Jeff Scott and colleagues told the journal Genome Biology.
Many other flies transmit important human diseases and hopefully this work will encourage further genome analyses of these disease vectors, and comparisons between them
Prof David Conway of the London School of Hygiene & Tropical Medicine
Houseflies are ideally suited to spreading disease. They have regular contact with carcasses, rubbish and other septic matter containing bacteria, viruses and other “nasties” such as tapeworms.
They enjoy some of the same food that we do, and because they are very good at evading our detection, they get plenty of opportunities to land on it (as well as on us).
It is believed that they carry so many pathogens because they feed on liquid or semi-liquid matter – often faeces. Their constant food intake, in turn, means that they need to evacuate large amounts of faeces – along with any pathogens they are carrying – whenever they land for more than a few seconds.
Unlike us, they don’t get sick from this dirty lifestyle.
Dr Scott and his team were intrigued to find out why and to see if it might be possible to utilise this skill for mankind’s benefit.
They sequenced the genomes of six female houseflies, creating a 691 Mb long sequence. They then compared it with the 123 Mb genome of the fruit fly, Drosophila melanogaster, to find which parts of DNA were unique to housefly, and could be candidates for further study.
The housefly had many more immune genes than Drosophila. Its immune genes were also more diverse – presumably to offer it protection against the numerous pathogens it carries.
Prof David Conway of the London School of Hygiene & Tropical Medicine said: “Although we often think of houseflies as just a nuisance, they can transmit many pathogenic bacteria to people and contribute significantly to disease in poor communities where sanitation is limited.
“It is great to see this analysis of the genome sequence, in particular its comparison with the genomes of fruit flies which have been more intensively studied until now.
“Several other flies transmit crucial human diseases and it is expected that this would work and encourage further genome analyses of these disease vectors, and comparisons between them.
The genome of the test fly, that can carry sleeping sickness especially in Africa, was published couple of months ago, although it survives on sucking blood, it is more closely related to the housefly than generally believed to be mosquitoes. Also, there are several other vectors of infamous diseases that will be comprehended in a much better way if there were more comparisons of their genomes.