Darwin 200 - "Blogging the Origin" on ScienceBlogs

Possibly the first tree of species descent, from Darwin's notebooks, 1837I picked up on this new blog at ScienceBlogs - "Blogging the Origin" via Science's Origins blog.  In this blog, science writer and evolutionist John Whitfield, who bravely admits to never having read The Origin of Species before, is conducting a book club cum blog as he reads the text, chapter by chapter in this anniversary year.  As I write, he's covered the Introduction and Chapters 1 and 2, with the next instalment due on Friday.  He plans to finish in time to celebrate Darwin's 200th birthday.

I haven't read The Origins since I was a teenager (which is an upsettingly long time ago), and this has inspired me to read it again.  But which version?   The old Pelican paperback edition I read all those years ago is a later edition of the tome, while the edition reprinted in the compilation From So Simple a Beginning", edited by E. O. Wilson, is I think the first edition (but lacks a certain portability - the volume also has Voyage of the Beagle, Descent of Man and The Expression of Emotions, all in a hardback binding).  Perhaps I should limit myself to the 1858 pair of papers by Darwin and Wallace?

"Clifford Longley has been silly"

Well, Andrew Brown (in who's blog at the Guardian I first read Clifford Longley's dopey ASA complaint) has written a little bit more about the affair, and judges that "Clifford Longley has been silly".  At least it would seem that the text that Longley appears to have sent to newspaper columnists up and down the country was sent by him.

His defence is that the quotes are genuine even if he did not collect them and he that he never claimed to have collected them himself. It didn't seem to him the important thing about them. Some of them he had in his own library, or could remember reading; others were new to him, but all seemed germane to his general point, that there are distinguished scientists who take the strong anthropic principle seriously as evidence for design in the universe. This was the point he wanted to make to the ASA, which offers a web form for complaints on its web site into which he cut and pasted what he had found. 

This is just astonishing.  He didn't just cull the quotes, he did wholesale plagiarism and didn't even check the quotations for accuracy.

In his defence, I would say that he has not spent much time on the web, and was ignorant of the long history of viciously argued warfare over creation and evolution on there and of the habit of judging content by the site on which it appears. 

Well, he used to run a home page (moribund since 2002 as far as I can tell).  And anyone with interests in religious affairs who uses the internet ought to know that evolution vs creation arguments ranges far and wide - if they don't know this, they are not competent commentators.

What a foolish course of action Longley has taken.

Internet Watch Foundation in the news again

The Register reports that the UK ISP Demon has removed access to a larcge chunk of internet history.  The error pages that users are presented with apparently imply this is in response to the site being listed on the IWF blacklist.  Amusingly, El Reg reports:

One Demon customer tells us he was unable to visit archived versions of websites run by the BBC, Parliament, the United Nations, the Internet Watch Foundation, Demon Internet, and Thus. In other words, this customer points out, Thus is blocking its own web history. "It is nuts," he says.

This does seem to be using a sledgehammer to crack a nut.  I presume there are dubious sites archived at the wayback machine, but to block the lot seems a bit extreme.  Presumably the internet block derives from the way Demon have sought to implement the IWF blacklist.

Visitor Map

Here is a visitor map - it should show where visitors are located!

In the Journals - Mosquito lifespan and Dengue fever control

ResearchBlogging.org

Many tropical diseases are transmitted by insect vectors - malaria (which is caused by Plasmodium parasites) and yellow fever (caused by a virus) being examples of diseases transmitted by Anopheles and Aedes mosquitoes respectively.  Dengue fever is another viral disease that is transmitted by Aedes aegypti.  One crucial feature of the disease transmission cycle is that once the disease organism is collected by the mosquito in a blood meal, it takes some time to develop within the insect before it becomes infectious.  In the case of both malaria and dengue fever, this period of time is about two weeks.  This paper evaluates the use of the endosymbiotic bactera Wolbachia to shorten mosquito lifespan in the hope that this will reduce disease transmission.

In a sense, this is an attractive strategy, and one that makes use of one of the properties of some Wolbachia strains to shorten host lifespan. I have previously blogged about some aspects of Wolbachia biology in the immune system of insectsWolbachia infection is maternally transmitted, and spreads through insect populations because of a reproductive drive known as cytoplasmic incompatibility (CI) - infected females mated to uninfected males yield infected offspring, while uninfected females mated to infected males yield no offspring.  This reproductive drive is presumably sufficient to drive even strains of Wolbachia which have negative effects on viability (such as reduced lifespan) through the population.

The Wolbachia strain used here is known as wMelPop, and shortens the lifespan of infected Drosophila.  It was adapted to A. aegypti by propagating it in an A. aegypti cell culture for three (!) years, before generating an infected A. aegypti strain by injection of embryos.  Comparison of lifespan survival curves of the infected strain (PGYP1 with the original, uninfected, mosquito strain (JCU) showed significant reduction in lifespan, at both 25 and 30 degrees.  Further expeiments investigated the impact on lifespan when the mosquitoes were raised in more "realistic" environmental conditions of fluctuating temperature and humidity, where it was found that the median lifespan of infected females was significantly reduced, from about 50 days, to about 21 days.  These effects on lifespan could be "cured" by treatment with the antibiotic tetracyclin, which kills Wolbachia.

The infected strain shows the appropriate CI characteristics (i.e. infected males crossed to uninfected females yield no offspring), and this is maintained as the males age.

So, is this a realistic strategy for dengue control? Well, I guess the signs are good, but I always worry about the capacity of natural selection to throw a spanner in the works.  Just as in the past malarial drug resistance has arisen as has mosquito resistance to DDT, I can;t help but worry that the complex interaction between mosquito and Wolbachia is going to be subject to a variety of selection pressures that may have unintended consequences. 

 

C. J. McMeniman, R. V. Lane, B. N. Cass, A. W.C. Fong, M. Sidhu, Y.-F. Wang, S. L. O'Neill (2009). Stable Introduction of a Life-Shortening Wolbachia Infection into the Mosquito Aedes aegypti Science, 323 (5910), 141-144 DOI: 10.1126/science.1165326