Amazing feet of science: Researchers sequence the centipede genome

cjb250 — Tue, 25 Nov 2014 19:00:01 +0000

An international team comprising more researchers than the arthropod has legs (106 researchers) has sequenced the genome of Strigamia maritima, a Northern European centipede, and found that its genome, while less than a tenth the size of a human’s, has around two-thirds the number of genes, distributed across one pair of large chromosomes and seven pairs of tiny ones, including X and Y sex chromosomes. ̽��ֱ��results are published today in the journal PLOS Biology.

Arthropods are the most species-rich group of animals on Earth. There are four classes of arthropods alive today: insects, crustaceans, chelicerates (which include spiders and scorpions) and myriapods. This latter class, which includes centipedes, is the only class for which no genome has yet been sequenced.

Myriapods arose most likely from marine ancestors that invaded the land more than 400 million years ago. All myriapods have a large number of near-identical segments, most bearing one or two pairs of legs. However, despite their name, centipedes never have a hundred legs. Strigamia maritima, which lives in coastal habitats, can have from 45 to 51 pairs – but the number of pairs is always odd, as it is in all centipedes.

̽��ֱ��team found that the centipede genome is more conserved than that of many other arthropods, such as the fruit fly, with less gene loss and scrambling. This suggests that the centipede has evolved slowly from their common ancestor and should allow researchers to draw comparisons between very different animals, which are not obvious when working with fruit flies or other fast evolving insects. For example, the researchers found parallels in the way that the brain is patterned between centipedes and other very distantly related animals such as marine worms. Such comparisons will enable scientists to build an overall picture of how genetic changes underlie the diversity of all animals.

“With genomes in hand from each of the four classes of living arthropod, we can now begin to build a picture of the genetic make-up of their common ancestor,” says Dr Frank Jiggins, of the Department of Genetics at the ̽��ֱ�� of Cambridge, one of the researchers involved “For example, by comparing flies and mosquitoes with centipedes, we have shown that the innate immune systems of insects are much older than previously appreciated.”

One of the most surprising findings is that these centipedes appear to have lost the genes encoding all of the known light receptors used by animals, as well as the genes controlling circadian rhythm, the body clock.

“Strigamia live underground and have no eyes, so it is not surprising that many of the genes for light receptors are missing, but they behave as if they are hiding from the light. They must have some alternative way of detecting when they are exposed,” says Professor Michael Akam, Head of the Department of Zoology at Cambridge and one of the lead researchers. “It’s curious, too, that this creature appears to have no body clock – or if it does, it must use a system very different to other animals.”

̽��ֱ��centipede’s genome sequence is of more than just scientific interest, argues Professor Akam. “Some of its genes may be of direct use. All centipedes inject venom to paralyse their prey,” he explains. “Components of venom often make powerful drugs, and the centipede genome will help researchers find these venom genes.”

Reference
Chipman, AD et al. ̽��ֱ��First Myriapod Genome Sequence Reveals Conservative Arthropod Gene Content and Genome Organisation In the Centipede Strigamia maritima. PLOS Biology; 25 Nov 2014

What it lacks in genes, it certainly makes up for in legs: the genome of the humble centipede has been found to have around 15,000 genes – around 7,000 fewer than a human.

Strigamia live underground and have no eyes, so it is not surprising that many of the genes for light receptors are missing, but they behave as if they are hiding from the light

Michael Akam

Anthony Barber

Strigamia maritima male, Loch Linnhe, Scotland

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In search of Life at Lady Mitchell Hall

bjb42 — Fri, 27 Jan 2012 09:00:57 +0000

‘Life’ is the subject for 2012, as all eight lectures will delve into the many aspects of this broad yet compelling topic from various disciplines. Previous themes in years past include Beauty, Risk, Identity, Conflict, and Survival.

Life as a cell, life in a military field hospital in Afghanistan, and life after death are some of the topics explored in the multi-disciplinary lecture series. ̽��ֱ��first lecture entitled From Genomes to the Diversity of Life was presented on 20 January by Professor Michael Akam of the ̽��ֱ�� of Cambridge. Subsequent talks will be held by Professor Frances Ashcroft from Oxford ̽��ֱ��, Cambridge’s own Dr Robert Macfarlane, Dr Michael Scott, Dr Mark de Rond, Professor Chris Bishop, and Professor Ron Laskey. ̽��ֱ�� ̽��ֱ�� of Southampton’s Professor Clive Gamble concludes the series with his talk: ̽��ֱ��After Life.

̽��ֱ��Darwin College lecture series began in 1986 and has proved to be one of the most sought after events in Cambridge ever since. ̽��ֱ��series marks one of the key events at Darwin College and has run every year from January to March since inception.

̽��ֱ��lectures continue from 27 January and continues every Friday for six weeks at 5.30pm at the Lady Mitchell Hall. Because the annual series is extremely popular, organisers suggest that anyone hoping to attend should arrive early to ensure a place. ̽��ֱ��organisers have also secured an adjacent theatre with live television coverage so that those who are unable to secure a place in the main hall are able to still view the lecture.

̽��ֱ��continuing schedule is as follows:

27 January, Dr Robert Macfarlane, ̽��ֱ�� of Cambridge Life in Ruins

03 February, Professor Frances Ashcroft, ̽��ֱ�� of Oxford ̽��ֱ��Spark of Life

10 February, Dr Michael Scott, ̽��ֱ�� of Cambridge Life in the Ancient World

17 February, Dr Mark de Rond, ̽��ֱ�� of Cambridge Life in Conflict

24 February, Professor Ron Laskey, ̽��ֱ�� of Cambridge Life and Death of a Cell

02 March, Professor Chris Bishop, ̽��ֱ�� of Cambridge Artificial Life

09 March, Professor Clive Gamble, ̽��ֱ�� of Southampton ̽��ֱ��After Life

Past lectures are also available on iTunes, and Darwin College Lecture books are available from the Cambridge ̽��ֱ�� Press.

Darwin College continues the popular Darwin College lecture series this week on 27 January with Life in Ruins. ̽��ֱ��annual eight week series held at Lady Mitchell Hall is free to the public and is renowned for its famous speakers and thought-provoking discussions.

̽��ֱ��annual series is popular as organisers suggest that anyone hoping to attend should arrive early to ensure a place.

Darwin College

Darwin College Lecture Series 2012

This work is licensed under a Creative Commons Licence. If you use this content on your site please link back to this page.

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̽��ֱ�� of Cambridge - Michael Akam

Amazing feet of science: Researchers sequence the centipede genome

In search of Life at Lady Mitchell Hall