horizontal gene transfer
edyong | March 17, 2010In Robert Louis Stevenson's classic story, Dr Henry Jekyll drinks a mysterious potion that transforms him from an upstanding citizen into the violent, murderous Edward Hyde. We might think that such an easy transformation would be confined to the pages of fiction, but a similar fate regularly befalls a common fungus called Fusarium oxysporum.
A team of scientists led by Li-Jun Ma and Charlotte van der Does have found that the fungus can swap four entire chromosomes form one individual to another. This package is the genetic equivalent of Stevenson's potion. It has everything a humble, Jekyll…
edyong | February 14, 2010
Millions of people in Latin America have been invade by a parasite - a trypanosome called Trypanosome cruzi. They are passed on through the bite of the blood-sucking assassin bug and they cause Chagas disease, a potentially fatal illness that affects the heart and digestive system. The infections are long-lasting; it can take decades for symptoms to show and a third of infected people eventually die from the disease. But T.cruzi does much more than invade our flesh and blood; it also infiltrates our genomes.
T.cruzi is unusual in that a massive proportion of its DNA, around 15-30%, lies…
edyong | July 30, 2009This article is reposted from the old Wordpress incarnation of Not Exactly Rocket Science.
A humble species of fruit fly is the genetic equivalent of a Russian doll - peer inside its DNA and you will see the entire genome of a species of bacteria hidden within.
The bacteria in question is Wolbachia, the most successful parasite on earth and infects about 20% of the world's species of insects. It's a poster child for selfishness. To further its own dynasty, it has evolved a series of remarkable techniques for ensuring that it gets passed on from host to host. Sometimes it gives infected…
edyong | July 16, 2009Compare the elegant grace of a running wolf with the comical shuffle of a waddling dachshund, and you begin to understand what millennia of domestication and artificial selection can do to an animal. As dachshunds develop, the growing tips of their limb bones harden early, stunting their growth and leading to a type of dwarfism called chondrodysplasia. The same applies to at least 19 modern breeds including corgis, Pekingese and basset hounds, all of which have very short, curved legs.
These breeds highlight the domestic dog's status as the most physically diverse of mammals. Now, a team of…
edyong | May 1, 2009For centuries, farmers have been genetically modifying their plants without even knowing it. That's the message from German scientists who found that grafting, a common technique used to fuse parts of two plants together, causes the two halves to swap genes with each other.
Grafting can involve fusing the stem of one plant (the scion) to the roots of another (the stock), or a dormant bud to another stem. There are many reasons for this - sometimes it's the most cost-effective way of cultivating the scion, sometimes the stock has properties that the scion lacks including hardiness or…
sporte | April 22, 2009That's how new life forms are created every day in the wild, folks. Human researchers of course have added a few twists on the theme. If we can't induce bacteria or animal cells to collect new bits of DNA on their own, we turn to electroshock therapy. With plants.... aw heck, we just shoot them.
And where did this crazy rant come from you ask? Last Saturday morning, at the crack of 9 am I got to be interviewed on a radio program with two of the main spokespeople from the DIY bio movement, Mackenzie Cowell and Meredith Patterson.
The program was "The Food Chain" (you can listen to it…
edyong | March 5, 2009The world of genetics is filled with stories that are as gripping as the plot of any thriller. Take the IRGM gene - its saga, played out over millions of years, has all the makings of a classic drama. Act One: setting the scene. By duplicating and diverging, this gene thrived in the cells of most mammals as a trinity of related versions that played vital roles in the immune system.
Act Two: tragedy strikes. About 50 million years ago, in the ancestors of today's apes and monkeys, the entire IRGM cluster was practically deleted, leaving behind a sole survivor. Things took a turn for the worse…
edyong | February 12, 2009This is the seventh of eight posts on evolutionary research to celebrate Darwin's bicentennial. It combines many of my favourite topics - symbiosis, horizontal gene transfer, parasitic wasps and viruses.
Parasitic wasps make a living by snatching the bodies of other insects and using them as living incubators for their grubs. Some species target caterpillars, and subdue them with a biological weapon. They inject the victim with "virus-like particles" called polydnaviruses (PDVs), which weaken its immune system and leave the wasp grub to develop unopposed. Without the infection, the wasp egg…
edyong | February 1, 2009The Japanese pinecone fish searches for food with living headlights. This ÂÂhand-sized fish harbours colonies of light-producing bacteria in two organs on its lower jaw. The beams from these organs shine forward, and when night falls and the fish goes searching for food, its jaw-lamps light the way.
Elsewhere in the Pacific Ocean, the Hawaiian bobtail squid also uses luminous bacteria, but theirs act as a cloaking device. They produce a dim glow that matches the strength of moonlight from above, hiding the squid's silhouette from hungry fish below. It's a mutual relationship; the squid gets…
edyong | December 28, 2008Solar power is a relatively new development for humans but, of course, many living things have been exploiting the power of the sun for millions of years, through the process of photosynthesis. This ability is usually limited to plants, algae and bacteria, but one unique animal can do it too - the emerald green sea slug Elysia chlorotica. This remarkable creature steals the genes and photosynthetic factories of a type of algae that it eats (Vaucheria littorea), so that it can independently draw energy from the sun. Through genetic thievery, it has become a solar-powered animal and a…
edyong | November 3, 2008Mammals like ourselves pass our genes 'vertically' from parent to child. But bacteria aren't quite so limited; they have mastered the art of gene-swapping and regularly transfer DNA 'horizontally' from one cell to another. This "horizontal gene transfer" has been largely viewed as a trademark of single-celled organisms, with few examples among animals and plants. That is, until now.
A group of American researchers have discovered a group of genetic sequences that have clearly jumped around the genomes of several mammals, one reptile and one amphibian. It's the most dramatic example yet that…
edyong | August 6, 2008Viruses may cause disease but some can fall ill themselves. For the first time, a group of scientists have discovered a virus that targets other viruses. This new virus-of-viruses was discovered by Bernard La Scola and Christelle Desnues at the University of the Mediterranean, who have playfully named it Sputnik, after the Russian for "fellow traveller". It is so unique that they have classified it in an entirely new family - the "virophages" - in honour of the similarities it shares with the bacteriophage viruses that use bacteria as hosts.
The story of Sputnik started in 1992 with some…
edyong | June 1, 2008
You inherited your genes from your parents, half from your father and half from your mother. Almost all other animals contend with the same hand-me-down processes, but not the bdelloid rotifers. This intriguing group of small freshwater creatures are not content with their genetic hand-me-downs; they import genes too. A new study shows that their genomes are rife with legions of foreign DNA, transferred from bacteria, fungi and even plants.
The swapping of genetic material is all part of a day's activity for bacteria but it's incredibly rare in animals. But bdelloids are bringing in…