Tuesday, March 2, 2010

Molecular machines and memorable African genomes in my Picks of the Week from RB

Another week has gone by and some very interesting molbio blog posts have been aggregated to Researchblogging.org. Every week [see my opening post on the matter], I'll select some blog posts I consider particularly interesting in the field of molecular biology [see here to get a sense of the criteria that will be used], briefly describe them and list them here for you to check out.

Note that I'm only taking into consideration the molbio-related blog posts aggregated under "Biology".

Congratulations to everyone who got their post selected.

1) Molecular machines participate in several biological processes and their evolution is a fascinating and fundamental question. The mitochondria, organelle derived from an α-proteobacterial endosymbiont, relies on such assemblies for correct functioning. For example, many genes coding for important mitochondrial proteins have been transferred to the nuclear genome and are synthesized in the cytoplasm: the importing of these proteins into this organelle is mediated by the action of the 4 membrane-embedded molecular machines.

(…) how could these molecular import machines evolve? No bacteria have protein complexes that import proteins over their double membrane, so where did these complexes come from and how did they acquire the functionality that they have now? (From the selected post)
Lucas Brouwers at Thoughtomics discusses an interesting paper reporting the use of protein transport machines in mitochondria as a model system to study how sophisticated molecular machines can evolve from simpler components.

From the paper:
We proposed that simple “core” machines were established in the first eukaryotes by drawing on pre-existing bacterial proteins that had previously provided distinct functions.

2) The genomes of an indigenous hunter-gatherer from the Kalahari Desert and a Bantu from southern Africa have recently been reported.

Modern humans arose in Africa about 250 000 years ago and only spread out to Europe and the rest of the world in the last 60 000 years, displacing Homo erectus in the process. The migrants that founded the modern European, Asian and American populations would have carried with them only fraction of humanity's genetic diversity when they left Africa but until recently genomics has focused on those populations. (from the selected post)

The indigenous hunter-gatherer people of southern Africa represent one of the oldest known lineages of modern humans. The genetic structure of these individuals, then, is important for understanding human diversity. David at The Atavism comments on the article and its implications.

Archbishop Desmond Tutu, the Bantu individual selected (Image source)

That's it for this week. Stay tuned for more MolBio Research Highlights!

ResearchBlogging.orgSome of the articles discussed in this week's selected posts:

Clements, A., Bursac, D., Gatsos, X., Perry, A., Civciristov, S., Celik, N., Likic, V., Poggio, S., Jacobs-Wagner, C., Strugnell, R., & Lithgow, T. (2009). The reducible complexity of a mitochondrial molecular machine Proceedings of the National Academy of Sciences, 106 (37), 15791-15795 DOI: 10.1073/pnas.0908264106

Schuster SC, Miller W, Ratan A, Tomsho LP, Giardine B, Kasson LR, Harris RS, Petersen DC, Zhao F, Qi J, Alkan C, Kidd JM, Sun Y, Drautz DI, Bouffard P, Muzny DM, Reid JG, Nazareth LV, Wang Q, Burhans R, Riemer C, Wittekindt NE, Moorjani P, Tindall EA, Danko CG, Teo WS, Buboltz AM, Zhang Z, Ma Q, Oosthuysen A, Steenkamp AW, Oostuisen H, Venter P, Gajewski J, Zhang Y, Pugh BF, Makova KD, Nekrutenko A, Mardis ER, Patterson N, Pringle TH, Chiaromonte F, Mullikin JC, Eichler EE, Hardison RC, Gibbs RA, Harkins TT, & Hayes VM (2010). Complete Khoisan and Bantu genomes from southern Africa. Nature, 463 (7283), 943-7 PMID: 20164927

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