Why do we laugh? Is there any evolutionary significance? Well, instead of pondering about these questions… why not tickle a primate to find it out?
Humans aren’t the only ones who like it in the armpit. Our fellow great apes — orangutans, chimps, bonobos and gorillas — also squeal in response to tickling, and new research shows this behavior may be the evolutionary root of human laughter.
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Laughter is a key component of social interaction in humans. Humans are 30 times more likely to laugh when in the company of other humans than not, and tickling is inherently social — no animal is capable of tickling itself. Understanding the origins of laughter can also lend insight to the evolution of language, as both behaviors involve breath control and vocal cord vibrations.
I know that we all take a lite attitude when talking about shark fin soup in the lab, but it really is a serious issue. After watching the documentary “Sharkwater” on youtube.com, which is about shark fining, I was shocked. I am definitely changing my tone about being open minded to trying any new food and will now have shark fin soup as my exception. I personally was unaware that the fin industry was so corrupt, dishonest, and dangerous. I think this movie is completely worth the 1 hour and 16 minutes to watch. You can go to youtube.com and search “Sharkwater” and the movie comes up in 9 segments about 10 minutes each. Hope you all take the time to watch it and see the truth behind this dish.
I do want to clarify that I don’t think that the shark fin soup dish should be done away with all together. However, I do think there needs to be a world wide push controlling the number of sharks harvested and also the methods of capture used in harvesting these animals. The ocean is a vast area and it will take all countries working together to protect the sea and it’s sharks.
There are so many different kinds of neurons in the brain and they control all sorts of mechanisms. In C.elegans, several dopamine(a neurotransmitter) -secreting neurons are differentiated from different lineage, but they are all producing dopamine. This has raised an interesting question: are the genes controlling the dopamine synthesis regulated differently or the same way in different dopamine-secreting neurons?
A recent study by Nuria Flames & Oliver Hobert from Columbia University has revealed the latter is true. They made extensive promoter constructs of all the genes involved in dopamine production (which is a good example for those of us who are going to do similar promoter analyses). Their results showed all five genes were regulated by the same regulatory element, presumably by the same transcription factor(s). Therefore, these dopamine synthesis genes are regulated the same way in different dopaminergic neurons. More importantly, they have also found that this regulatory mechanism is conserved in mice!
This is the terminal differentiation we have just discussed. The study has demonstrated that this differentiation circuit is modular and has been incorporated in different types of dopaminergic neurons to carry out the same final function. In other words, the final output function of the gene network is the same while the upstream specification architecture can be quite different.
Reference
Flames N, Hobert O. Gene regulatory logic of dopamine neuron differentiation. Nature. 2009 Apr 16;458(7240):885-9. [PubMed][Nature][Commentary in Nature]
Scientists have found out that night owls can work longer and be more alert late at night. As simple as that.
Researchers found that in tests those who consider themselves more alert in the morning can concentrate for less time than those who work best at night.
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The results, reported in the journal Science, suggest that night owls generally outlast early birds in the length of time they can be awake before becoming mentally fatigued.
References:
Night owls can work longer than early birds, scientists find [Telegraph]
Schmidt C, Collette F, Leclercq Y, Sterpenich V, Vandewalle G, Berthomier P, Berthomier C, Phillips C, Tinguely G, Darsaud A, Gais S, Schabus M, Desseilles M, Dang-Vu TT, Salmon E, Balteau E, Degueldre C, Luxen A, Maquet P, Cajochen C, Peigneux P. Homeostatic sleep pressure and responses to sustained attention in the suprachiasmatic area. Science. 2009 Apr 24;324(5926):516-9. [PubMed][Science]
People with Down’s syndrome rarely get most kinds of cancer and U.S. researchers have nailed down one reason why — they have extra copies of a gene that helps keep tumors from feeding themselves.
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“One such gene is Down’s syndrome candidate region-1 (DSCR1, also known as RCAN1),” Harvard’s Sandra Ryeom and colleagues wrote.
This gene codes for a protein that suppresses vascular endothelial growth factor or VEGF — one of the compounds necessary for angiogenesis.
References:
Down’s syndrome reveals one key to fighting cancer [Reuter]
Baek KH, Zaslavsky A, Lynch RC, Britt C, Okada Y, Siarey RJ, Lensch MW, Park IH, Yoon SS, Minami T, Korenberg JR, Folkman J, Daley GQ, Aird WC, Galdzicki Z, Ryeom S. Down’s syndrome suppression of tumour growth and the role of the calcineurin inhibitor DSCR1. Nature. 2009 May 20. [PubMed][Nature]
A fundamental but elusive step in the early evolution of life on Earth has been replicated in a laboratory.
Researchers synthesized the basic ingredients of RNA, a molecule from which the simplest self-replicating structures are made. Until now, they couldn’t explain how these ingredients might have formed.
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No matter how they combined the ingredients — a sugar, a phosphate, and one of four different nitrogenous molecules, or nucleobases — ribonucleotides just wouldn’t form. Sutherland’s team took a different approach “and successfully synthesized RNA” in a laboratory conditions resembled those of the life-originating “warm little pond”.
References:
Life’s First Spark Re-Created in the Laboratory [Wired]
Powner MW, Gerland B, Sutherland JD. Synthesis of activated pyrimidine ribonucleotides in prebiotically plausible conditions. Nature. 2009 May 14;459(7244):239-42. [PubMed][Nature]
We briefly mentioned the idea of silent mutation in the lab meeting the other day when we discussed how DNA mutations can cause diseases. In general, a polymorphism in the wobble (3rd) position of the DNA codon often would not change the amino acid sequence. However, that doesn’t mean everything would be the same or the polymorphism would have no effect on the resulting system. It has long been known that there is codon bias, the preference of using particular codons, among different organisms. This may have implications on the fitness of the animals and evolution.
Josh Plotkin’s group at the University of Pennsylvania has recently done a very interesting study on this topic in Science magazine. They synthesized a synthetic library of 154 green fluorescent protein (GFP) with an average of 114 silent mutations between each pair. They found the expressing of these GFPs in E. Coli, as measured by fluorescence of the GFP, can vary as much as 250 fold! Further analyses revealed that this expression difference did not correlate with the codon bias but more to the secondary structures of the RNA.
As it turned out, RNA with more stable secondary structure was harder to be translated into protein and hence a lower expression level. Also, the stability near 5′ start codon explained most of the expression variation, which indicates the rate limiting step of gene expression was primarily translation initiation. They further predicted and experimentally validated GFP variants with rare codon usage, which presumably were more difficult to produce, would be highly expressed if attached with a 5′ sequence with weaker RNA secondary structure. Therefore silent mutations are not that silent after all, it depends on whether you have the right ear to hear.
Reference
Kudla G, Murray AW, Tollervey D, Plotkin JB. Coding-sequence determinants of gene expression in Escherichia coli. Science. 2009 Apr 10;324(5924):255-8.Click here to read [PubMed][Science]
I am proposing an outing later in the summer, and we may ask the 2nd floor people to join in. In fact I have talked to some people about this idea. We can also come to my place for movies from time to time.
