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October 2014
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Earth Sciences Seminar Room (Basement, WEB 05, the previous Mineralogy Seminar Room)

 

Wednesday 29th October  4.00 pm

 

Dr. Laurence A.J. Garvie, Center for Meteorite Studies, Tempe AZ 85287-6004 (lgarvie@asu.edu)

 

In 1806 a black, friable meteorite fell near the town of Alais in France. Subsequent chemical analysis published in the same year by Thenard showed that the stone contained 2.5 parts carbon and 18.5 parts water. In 1834, Berzelius showed that the stone contained clays and a complex suite of organic materials that were extracted with water. This study heralded the field of extraterrestrial organic chemistry.

 

The Alais stone belongs to a class of meteorites called carbonaceous chondrites (CC). These chondrites are primitive meteorites composed of various proportions of chondrules and refractory materials set in a fine-grained matrix. Their study provides important information on early Solar System processes. In addition, the matrix of these meteorites harbors a suite of presolar materials, some of which are carbonaceous.

 

Today, more than 40,000 organic compounds have been recognized in the CC meteorites, including more than 100 amino acids. Together with these soluble compounds, some CC meteorites contain an abundant carbonaceous component that is insoluble in water, solvents, and acids called the insoluble organic material (IOM). The IOM is chemically and structurally diverse and contains two easily recognizable and curious components – carbonaceous nanoglobules (also called organized elements) and nanodiamonds. I will explore the significance of these components to early Solar System studies as well as address the frequent past and present claims of indigenous microfossils in the carbonaceous chondrite meteorites.

 

 

 

More information on attending seminars at http://www.nhm.ac.uk/research-curation/news-events/seminars/

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Arthropod specimens and genome skimming: Extracting a large panel of diet, symbiotic and phylogenomic information

 

Benjamin Linard, Department of Life Sciences, NHM

 

Wednesday 15 October 1100

 

Sir Neil Chalmers seminar room, Darwin Centre LG16 (below Attenborough studio)

 

 

Genome skimming (GS) is the shallow sequencing of the DNA extracted from pooled specimens. This approach was successfully tested on plants to extract simultaneously chloroplast / mitochondria / rRNAs and nuclear markers for phylogenomics and ecological studies. We previously produced insect specimen pools, initially to generate hundreds of complete mitochondria but also skimming the nuclear genomes of the specimens and their gut content. We will describe here the promising potential of GS when applied to arthropods.

 

In particular, we will show: (1) how trophic interaction between aphid preys, ladybirds (Coccinellini specimens) and associated symbiont can be skimmed from gut contents; (2) why a large panel of DNA markers (mitochondria, coding regions, repeats) are systematically leachable from insect pools through GS; (3) why applying GS to field collected material could extend our knowledge of insect genome evolution and uncover several ecological messages.

 

ladybird small.jpg

 

More information on attending seminars at http://www.nhm.ac.uk/research-curation/news-events/seminars/