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Auckland Shell Club |
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Auckland Shell Club |
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August Meeting
We were privileged to have Professor Hamish Spencer speak to us on the subject of "Making and Using Evolutionary Trees for Molluscs".
Besides his work at the University of Otago, Hamish is also the Director & Principal Investigator at the Allan Wilson Centre for Molecular Ecology and Evolution. This institution is named after a New Zealand born scientist who came up with the famous "Out of Africa" hypothesis - the idea that all human beings are descended from one woman ("Mitochondrial Eve") who lived in Africa about 200,000 years ago.
Most of the work being done there was inspired by Allan Wilson, and uses the latest genetic tools to answer questions about evolution.
Hamish, who has been a member of our club for 46 years, describes himself as primarily an evolutionary biologist. All the work he does on molluscs is done because the molluscs provide a useful model system for his research.
Genetic technology has revolutionized animal taxonomy, including that of molluscs. This new technology has provided reliable ways of tracing the evolutionary history of groups of related species, which can then be depicted as evolutionary trees. These diagrams, also known as phylogenetic trees, can be drawn in different ways. Eg. horizontal, vertical, or circular. The branches have different lengths that reflect how much genetic change has gone on in that particular branch, and from the amount of genetic change we can infer how much evolutionary time has passed.
Groups of organisms that sprout from individual branches are known as "clades", and their close proximity implies that they are all descended from a common ancestor. Numbers on the branches are a measure of how much genetic evidence there is for those particular branches, and also the degree of genetic variation.
The creation of a phylogenetic tree starts with Lab technicians who, with the help of incredible technology, identify the DNA sequence of a specific gene from each tissue sample. This DNA sequence is comprised of four letters (A, C, G, T) that stand for the different chemicals which make up the DNA molecule. Past genetic research has shown that a particular mitochondrial gene named C01 is very good for identifying species, however other genes are better suited for other types of investigation. C01 is called the barcoding gene because it can be used to very quickly determine what species something is. The genetic information is eventually fed into a computer which can automatically construct a phylogenetic tree based on the differences found in the decoded genes.
Hamish gave us some examples of how this technology has solved puzzles about New Zealand's molluscan fauna.
Top shells were an ideal group to study the co-evolution of molluscs with their parasites because several different species co-exist in close proximity. By determining which species of parasitic trematode infects which species of Diloma, they managed to shed some light on the co-phylogeny that had been observed between birds and their parasitic feather lice.
Normally species are clearly delineated by their DNA, but sometimes the results are ambiguous and the differences don't resolve very well. Sometimes it turns out that organisms regarded as separate species turn out to be genetically very similar. These issues were encountered in a study of our limpet genus Notoacmaea. DNA analysis of specimens from all around New Zealand produced some interesting results.
It proved that the narrow shelled limpets living on Zostera sea grass and some of the round shelled limpets living nearby on cockle shells are the same species (N. scapha). This finding allowed DOC to take N.scapha off the endangered species list. But the DNA analysis also proved that there were many more species than can be determined by physical appearance alone. For more information see "Molluscan Research 29(1): 33-59" which can be obtained from Magnolia Press at http://www.mapress.com/mr/.
Incidentally, DNA analysis also achieved the resurrection of Nerita melanotragus which had previously been synonymised with N.atramentosa, an Australian species.
The evolution of morphological novelty (Eg. how slugs evolved from snails) has also been studied. Although this process is a major physiology change, it has apparently occurred many times. The research indicates that it took somewhere between 2 to 5.1 million years for our Schizoglossa semi-slugs to evolve from a snail.
It was also proved that Schizoglossa novoseelandica barrierensis is actually more closely related to S.worthyae than S.novoseelandica.
Hamish is an excellent speaker and it was a very interesting evening.
More information about his many areas of involvement can be found at the following websites.
. University of Otago: http://www.otago.ac.nz/zoology/staff/spencer.html
. Allan Wilson Centre: http://www.allanwilsoncentre.ac.nz/
. Gravida Website: http://www.gravida.org.nz/
. NZ Mollusca Website: http://www.molluscs.otago.ac.nz
Next Meeting – Tuesday 10th September
Epsom Community Centre, 202 Gillies Avenue, Epsom at 7:30pm (doors open at 7pm). Supper provided.
Margaret Morley will host the meeting and cover a number of topics including more information about Epitonium, and also an upcoming trip to North Harbour, Kawau Island.
Betty Headford will then show us some old club photos from the archives.
The focus family will be freshwater mussels, so please bring along any specimens of these from your collection.
Shell Auction – Saturday 26th October
Our annual Shell Auction will be held on Labour Weekend at the Albany Hall.
Enclosed is the Auction Schedule.
Contact Peter Poortman (petermwp@gmail.com or 09 817 1397) for more information.
Poirieria Magazine
We welcome contributions to our club magazine "Poirieria".
Anything related to shells or collecting would be greatly appreciated - Eg. shelling trips/finds, personal observations/tips, scientific research, historic anecdotes, a notable washup, etc.
Please email articles to Peter Poortman at petermwp@gmail.com, or post to 26 Pendlebury Street, Green Bay, Auckland 0604.
Club Library
We have an extensive collection of books, magazines, and scientific publications available, as well as a biological microscope.
Other News
. Dr. Wilma Blom, the Marine Invertebrates Curator at Auckland Museum, reported on her recent trip to Vancouver to assess the "Dryer collection" of NZ and Australian shells. This is a huge collection (~15000 lots) including about 5000 land snail lots and many good Cenozoic fossil shells. The NZ shells were collected between 1919 and 1925, on a scale that may well have had a lasting impact on the local marine fauna. Auckland Museum will bring the collection back to NZ where it will be sorted and integrated into the Museum collection.
. Margaret Morley said that the currently stand-alone Douglas Manukau collection will soon be accessioned into the Auckland Museum collection.
. Hanieh Saeedi, a Ph.D. Candidate at the University of Auckland, is working on the Solenidae family. Although this family is absent from the NZ fauna, she would like to hear from anyone who may be able to provide some species of this family, either dry shell or ethanol-preserved specimens. Her email address is hanieh.saeedi@gmail.com
. The 10th Australian Shell Show will be held on 7-9th/February/2014 at the Balgowlah RSL Memorial Club 30-38 Ethel Street, Seaforth, Sydney, N.S.W. 2092. For more information email shellshow@sydneyshellclub.net. Michael Barlow (m.red.barlow@gmail.com or (09) 623 3231) has printed copies of the Show Schedule available for anyone who would like to have one.
. Items of interest for the monthly newsletter are always welcome - email to petermwp@gmail.com, or post to Peter Poortman, 26 Pendlebury Street, Green Bay, Auckland 0604.
