Science’s Silliest Stories – Science Museum Lates

Last week I ran an event at the adult-only Lates event at London’s Science Museum titled Science’s Silliest Stories. In it I told a story of some of the odder pieces of research that have been published recently to draw out some of the more curious sides of scientific research. I really enjoyed the evening. It was great to see friends who came and the audiences seemed to really get into it – perhaps the alcohol helped! Unfortunately I didn’t manage to record it (mainly to show my wife who was away with work), but here is essentially what I said:

Science’s Silliest Stories

Hello and welcome to science’s silliest stories.

In the next 20 minutes or so I will be regaling you with some of the sillier stories from science and scientific research. I’ll take you on a journey through real recent research, from animal sex, penises and vaginas, through to findings about wobbly pregnant women, levitating frogs and cheesy mosquitos. I’ll mention Sarah Palin’s now infamous quote about fruit fly research but hopefully leave you on a positive note that scientists aren’t always out to waste your tax money.
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How do you study circadian rhythms?

Science requires controlled and well-planned experiments. Without correct set-up, results from experiments may not be reliable enough to be trusted. Circadian biology is no different in that regard, and especially when trying to find out if something has a working circadian clock, controlled experiments are crucial. Continue reading “How do you study circadian rhythms?”

What is a circadian clock?

Broadly speaking, the circadian clock is a cell and molecular feedback loop – inside the cell, a bunch of proteins that interact with genes and DNA, which in turn interact back with those original proteins. This cellular feedback loop controls those outward and apparent rhythms we are aware of, like jet lag and waking, as well as many more we may be unfamiliar with, but it isn’t just humans who have a body clock, all life on planet Earth has one, although its workings aren’t exactly the same in all life-forms.

The feedback loop. Proteins join together to activate gene transcription of genes that subsequently repress the original proteins. This feedback generates oscillations of gene expression.
The feedback loop. Proteins join together to activate gene transcription of genes that subsequently repress the original proteins. This feedback generates oscillations of gene expression. From Eckel-Mahan and Sassone-Corsi, 2013, Metabolism and the circadian clock converge.

In animals, the key players are genes called clock, bmal, period and cryptochrome. There are actually multiple versions of the genes, named numerically (clock1a, bmal2, period3 etc) and shortened to 3 or 4 letters (clk1a, bmal2, per3 etc). To explain the cycle, we need to start with clock and bmal and go twice around the feedback loop, each stage showing the effect of the previous.

Firstly, CLOCK and BMAL proteins (CLK and BMAL; by consensus gene names are in italics and PROTEIN names are in uppercase), interact in the cell, joining together to turn on period and cryptochrome genes. As the genes are turned on, they are transcribed by the cell, eventually begetting proteins, PER and CRY proteins. These proteins interact with CLK and BMAL proteins to make CLK and BMAL less activating, repressing CLK and BMAL.

Secondly, as CLK and BMAL are now repressed, the turning on of period and cryptochrome genes is stopped. Fewer PER and CRY proteins are generated by the cell. Fewer PER and CRY proteins means less repression of CLK and BMAL, and so CLK and BMAL are released to begin another cycle.

The overall effect is similar in plants and other organisms: Activator proteins turn on repressor genes, these repressor genes are translated into repressor proteins by the cell and repress the activator proteins and so on. These proteins and genes in the clock aren’t the same in all organisms, but they play similar roles turning on or off genes, modifying the activity of proteins, like how David de Gea and Manuel Neuer are not the same player, but play similar roles for their teams. The fact that clocks have a similar feedback mechanism but consist of different components in the different branches of life adds to the idea that circadian clocks must be evolutionarily adaptive. It is an example of convergent evolution, where two separate species look similar without being evolutionarily related, such as how dolphins and sharks look fairly similar and are adapted to the broadly similar environments but are completely different species. In this case, evolution has dictated that the best body shape for fast and efficient swimming in water is a streamlined oval. In the case of circadian clocks, we can suggest that evolution has dictated that the best way of organising your physiology and behaviour is through the use of a molecular feedback loop which acts within the cells of the body.

 

Two illustrations of how the molecular components make up the circadian clock. On the left - in zebrafish. Clock (CLK) and bmal (BMAL) proteins (there are 6 versions) interact to activate (green arrow) transcription of per and cry genes. PER and CRY proteins then interact with CLK and BMAL to repress (green line with flat on top) their activity. Per and cry are also activated by light. On the right - plants. CCA1 and LHY are the CLK and BMAL equivatlents, interacting to activate PRR7 and PRR9 which then repress CCA1 and LHY.
Two illustrations of how the molecular components make up the circadian clock. On the left – in zebrafish. Clock (CLK) and bmal (BMAL) proteins (there are 6 versions) interact to activate (green arrow) transcription of per and cry genes. PER and CRY proteins then interact with CLK and BMAL to repress (green line with flat on top) their activity. Per and cry are also activated by light. Taken from Vatine et al., 2011, It’s time to swim! Zebrafish and the circadian clock. On the right – plants. CCA1 and LHY are the CLK and BMAL equivatlents, interacting to activate PRR7 and PRR9 which then repress CCA1 and LHY. Taken from Harmer lab at UC Davis

Zoos: Thoughts from time as a volunteer

Zoos are the place where a lot of people come into contact with exotic animals for the first time – especially in Britain, Western Europe and North America, where much of our ‘wild’ life has been decimated over time as humans have colonised the landscape. Exotic creatures seem to enthral people, especially children, and zoos can have a magical grasp over adventurous and inquisitive young minds – including those of sometimes world-weary adults.
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