Scientific Methods

Sunday, March 12, 2006

PARASITES: EVIDENCE FOR EARLY HUMAN INTERACTIONS

"Some head lice infesting people today were probably spread to us thousands of years ago by an extinct species of early human, a genetics study reveals. It shows that when our ancestors left Africa after 100,000 years ago, they made direct contact with tribes of "archaic" peoples, probably in Asia. Lice could have jumped from them on to our ancestors during fights, sex, clothes-sharing or even cannibalism."

http://news.bbc.co.uk/1/hi/sci/tech/3715132.stm


 
Dr Richard Knight
Co-ordinator: National Information Society Learnerships - Ecological Informatics
Department of Biodiversity and Conservation Biology
University of the Western Cape
Private Bag X17
Bellville 7535
 
Phone 27 + 21 + 959 3940
Fax 27 + 21 + 959 1237
 
 
 
 

5 Comments:

  • Give me some time to get hold of Dr. Ed Green, South Africa's specialist in lice (how weird), and does he know his stuff! I met Ed green at the 33rd Annual PARSA in 2003 at Manyane, Pilanesburg. Ed was the keynote speaker on the topic: "Comparative micromorphological specializations of the Phthiraptera (lice) as revealed by scanning electron microscopy." His views should be rather interesting. I will e-mail him tomorrow...

    David Vaughan

    By Blogger davidvaughan, at Sunday, March 12, 2006 10:06:00 PM  

  • Hi David

    I think this is goinf to be a really interesting study area.

    By Anonymous Rich Knight, at Tuesday, March 14, 2006 9:36:00 AM  

  • David Reed from the Florida Natural History Museum and his colleagues found a difference in the lineage of two head louse species infesting humans. One species is more common than the other, being found all over the globe, whereas the more rare species from the Americas is not found anywhere else in the world. Reed explains that the differences in the phylogeny are such that the two species must have evolved along different paths on different hosts, one being Homo erectus in the Americas, and the other, the line ultimately to Homo sapiens. This is where I get a little confused, as literature suggests that H. erectus was part of the lineage of modern humans, unless possibly a split in H. erectus to the Americas was a dead-end, and furthur develoment within the Homo genus took place primarily outside the Americas, and only later did H. sapiens again re-colonise the Americas...all while the lice in the latter situation had the resultant opportunity to adapt and mutate (and evolve) in co-existence with their Homo hosts. [Your comments please Doc. Knight?]

    Interestingly though, not everyone is supportive of Dr. Reed's claim, and suggest that an alternative explanation exists for the two vastly separate louse species. Dr. Mark Stoneking from the Max Planck Institute for Evolutionary Anthropology in Liepzig, Germany, feels that Dr. Reed's findings depend on the last common ancestor of the two species of lice, having lived about 1.2 million years ago. The calculation to get here depends on what the louse population was at that time, therefore, if the initial population estimates were incorrect, the results could be misleading, posing a false positive.

    I have e-mailed Dr. Reed to get his views on the topic, and if he responds, I will request his permission to post his response to this forum. In addition, Dr. Edward Green from MEDUNSA had pledged his support for supplying interesting information and SEM photographs of louse specialisations, which I am sure will be most interesting. Dr. Green also has some very interesting views on our generic topic and I have forwarded him the Blog address and Dr. Knights' e-mail contact address.

    I am still waiting for a response from the senior author of "The Human Genus," Dr. Wood about the questions presented to him about the reasons for his non-mention of Australopithecus afarensis and garhi, which, as I interpret it, gives more strength to his hypothesis of the rejection of Homo habilis and rudolfensis from the Homo genus...

    If you add the two, since Australopithecus afarensis and garhi also had a matrix of ape-like features as well as features similar to Homo, his hypothesis is somewhat weakened, and why leave out one of the most significant fossil finds in the first place?

    One thing to remember, if it is not there, does not necessarily mean it has no significance to shift balance. Half-truths in my opinion fit somewhere between integral science and hoaxes.

    Unfortunately, though independant of the above, a reality of science is that it relies on the integrity of the scientist to be delivered honestly, and many pressures including rank, money, peer-recognition, pride, credibility, can be temptatious motivations for seemingly harmless omision of truth or blatant falsifications.

    Cheers

    David Vaughan

    By Blogger davidvaughan, at Thursday, March 16, 2006 10:12:00 PM  

  • Dr. Knight, please visit the following site (below) for a rather amusing look at the possible roles of lice and their co-evolution. Maybe it would be an idea to insert some of the information which is relevant to other topics (as you will see)directly onto the blog from your administrative side?

    http://www.timothyjpmason.com/WebPages/Publications/Lice_Men.htm

    Cheers

    David Vaughan

    By Blogger davidvaughan, at Thursday, March 16, 2006 10:27:00 PM  

  • Hi David

    The mite story- I also read the article and frankly was confused. Firstly North America apparently had no hominids and the earlist fossils were 13 000 years old. Are you sure you mean N. America for Homo erectus and not S.E. Asia?

    My understanding is H. erectus left Africa very far back (more than one million years ago)- may even have left as H. ergaster and lived in Asia with his head lice but no body lice.

    Meanwhile back in Africa Homo sapiens evolved and with it a new species of mite evolved from the earlier species and became specialised on the body and clothes and that the head lice became extinct. Then when Homo sapiens left Africa 70 000 years ago or even slight more recently they brought this new body lice with them. Homo sapiens and Homo erectus did co-exist in Asia at the same time since the last Homo erectus fossil in Java are dated about 50 000 years ago. I think they must have meet in S.E. Asia and Homo sapiens got infected with the ancient head lice of Homo erectus. From Asia Homo sapiens moved to North America carrying both lice species.



    http://www.archaeology.org/9901/abstracts/early.html

    http://www.utexas.edu/courses/stross/ant322m_files/1stpersons.htm

    By Anonymous Rich, at Monday, March 20, 2006 8:30:00 AM  

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