a vagary of links

A “vagary”, according to The Source, is the collective noun for ‘impediments’. More pages that collect collective nouns are here and here. I am amused that a group of submarines is called a wolfpack, and that a group of sheldrakes is a doading (shoutout to my friend Duckie!).

Henceforth a group of links to things almost, but not quite entirely like tea relevant to The Thesis shall be known as a Vagary.

First, the Guardian reports on what most menstruating women know: that your hot water bottle really does relieve internal pain. A couple months back I read about a study that demonstrated that heat was as effective as ibuprofen in relieving menstrual pain. This is good news for our livers, no doubt, but carrying around a hot water bottle is impractical for about 99% of women. Those stick-on heat things with the iron filings in them seem to do a good job though!

Chocolate, it seems, is really not anti-depressant: “any mood benefits of chocolate consumption are ephemeral.” It’s just cos you’re stuffing your gob, not the magical woo-woo power of cacao.

Some gems from Medical Hypotheses, which I might unfairly characterise as a place where MDs who still yearn for the third-year undergraduate speculative essays they never got to write because they were too busy memorising the major craniofacial nerves get to, um, write those essays. Hey, it’s called Hypotheses for a reason. I kinda love this. I wish *I* had left-field theory to write up. Hours of fun.

Ecstacy makes you feel good and want to touch people and rub up against them and slide your–sorry. Ecstacy makes you feel saucy ‘cos of vasopressin and oxytocin. Man, that oxytocin stuff is awesome. It makes women forget the trauma and pain of childbirth, stimulates breastfeeding, makes you trust people more, increases your pain tolerance… why can’t I buy *that* from those guys at Camden Market instead of the magic mushrooms?

This one argues that there might be adaptive reasons behind our pervasive use of alcohol and caffeine. That is, caffeine makes us SMRT in an environment where competition is social/intellectual rather than physical, and alcohol dampens down the stress response in environments that lack social networks and cause a greater fear response. Oh, and apparently, if you’re drunk and in some sort of traumatic injury situation you heal better or something. This article is so unnecessarily convoluted in its prose I could only skim it, and it seems to be the kind of evolutionary psychology armchair handwaving that could be problematised pretty quickly; they don’t seem to have a grasp on their timelines (like, WHEN are these environments) or their cross-cultural caff/booze frequencies. But, you know, some testable hypotheses.

Cultural evolution causing baldness. I dunno in what sense cultural evolution is being used here, but possibly the loosest type, i.e. cultural change. Anyhow, apparently wearing headdresses and having close-cropped hair means sebum builds up on the hair shaft, and that’s bad and causes baldness. This is my favourite bit:

“Many people affected by common baldness have noted that they started to suffer from it during military service. This theory could explain this fact. The difference in hair length is the key. Military people, skinheads and others wear their hair short and therefore they can induce problems with the sebum flow. On the contrary, hippies, Hindus, etc. wear long hair.”

Dude. Good luck with that one.

Finally, the piece de resistance: defecating at night-time (only) may help you lose weight. Because you’re carrying your shit around with you all day, and that takes energy.

This gets the special face: o.O

paper: unexpected NRY chromosome variation in Melanesia

Unexpected NRY chromosome variation in Northern Island Melanesia
Scheinfeldt et al
Molecular Biology and Evolution, Advance Access
doi:10.1093/molbev/msl028

To investigate the paternal population history of populations in Northern Island Melanesia, 685 paternally unrelated males from 36 populations in this region and New Guinea were analyzed at 14 regionally informative binary markers and seven short-tandem-repeat loci from the non-recombining portion of the Y chromosome. Three newly defined binary markers (K6-P79, K7-P117, and M2-P87) aided in identifying considerable heterozygosity that would have otherwise gone undetected. Judging from their geographic distributions and network analyses of their associated short-tandem-repeat profiles, four lineages appear to have developed in this region and to be of considerable age: K6-P79, K7-P117, M2-P87, and M2a-P22. The origins of K5-M230 and M-M4 are also confirmed as being located further west, probably in New Guinea. In the 25 adequately sampled populations, the number of different haplogroups ranged from two in the single most isolated group (the Aita of Bougainville), to nine, and measures of molecular diversity were generally not particularly low. The resulting pattern contradicts earlier findings that suggested far lower male-mediated diversity and gene exchange rates in the region. However, these earlier studies had not included the newly defined haplogroups. We could only identify a very weak signal of recent male Southeast Asian genetic influence (<10%), which was almost entirely restricted to Austronesian (Oceanic) speaking groups. This contradicts earlier assumptions on the ancestral composition of these groups and requires a revision of hypotheses concerning the settlement of the islands of the central Pacific, which commenced from this region.

Have yet to digest this and its implications, will read it today and update. The emphasis is mine, as it is the intriguing part.

paper: phylogenetic classification and the universal tree

Doolittle, W.F. (1999) Phylogenetic classification and the universal tree. Science, 284, 2124-2128. [link]

Interesting review discussing recent findings which question a strict tree model for the universal tree of life. Lateral gene transfer is non-trivial, especial in archaeal and bacterial genomes. Doesn't dismiss the usefulness of molecular phylogenetics as a tool, but questions it as an end-goal (producing classifications).

If there were believable genealogies of all genes… one could then ask which genes have travelled together for how long in which genomes, without an obligation to marshal these data in the defense of one or another grander phylogenetic scheme for organisms.

Nifty figures, also.

ashkenazi founder event

The Matrilineal Ancestry of Ashkenazi Jewry: Portrait of a Recent Founder Event
Behar, D. M.; Metspalu, E.; Kivisild, T.; Achilli, A.; Hadid, Y.; Tzur, S.; Pereira, L.; Amorim, A.; Quintana-Murci, L.; Majamaa, K.

AMERICAN JOURNAL OF HUMAN GENETICS VOL 78; NUMB 3 (2006) pp. 487-497 

Both the extent and location of the maternal ancestral deme from which the Ashkenazi Jewry arose remain obscure. Here, using complete sequences of the maternally inherited mitochondrial DNA (mtDNA), we show that close to one-half of Ashkenazi Jews, estimated at 8,000,000 people, can be traced back to only 4 women carrying distinct mtDNAs that are virtually absent in other populations, with the important exception of low frequencies among non-Ashkenazi Jews. We conclude that four founding mtDNAs, likely of Near Eastern ancestry, underwent major expansion(s) in Europe within the past millennium.

Link 

paper: artificial cultural market

A new paper in Science [link]: Experimental Study of Inequality and Unpredictability in an Artificial Cultural Market by Salganik et al.

In a web experiment, the researchers created an artificial database of music (from unknown bands) and allowed people to download songs after rating them. In some conditions, people could see which songs had been downloaded more often, creating a social influence environment. Interestingly, how songs fared in each of eight different runs vaired widely, and mostly independently of how people rated “quality”.

The message seems to be that in music tastes at least, we are all sheep, and the first sheep to baaa makes a great difference to who gets on Top of the Pops.

paper: blondes have more… fear?

That’ll be the newspaper taglines, at least.

Behavioural inhibition in young children appears to be more frequent in blue-irised American children, and now in blond(er) German children. The putative link is made between melanocyte-stimulating hormones and cortisol (stress-related) stimulators as the underlying mechanism.

Interesting stuff, and will no doubt be picked up on for its quirk value, but it is the kind of research that is a little “so what?” in terms of what one does with that information. Cuddle fair-headed kids more? I bet they already get a little more attention 😉

I do get a bit antsy at the use of cross-cultural to describe findings such as these. I suppose it depends on where your draw your cultural boundaries (and for what purposes), but the danger is that “cross-cultural” is so very easily conflated with “human universal”. If we’re speaking of worldwide cultural variation, Caucasian Americans and Germans are pretty close to sister-taxa.

via Dienekes

paper: echolocation in bats

Once upon a time I considered becoming an evolutionary bat biologist1. Bats are cool. They’re close to primates on the mammal phylogeny, they have interesting social systems, and some of them have astoundingly sophisticated echolocation systems.

Gareth Jones and Emma Teeling have a paper in TREE: The evolution of echolocation in bats, discussing the phylogenetic history of this trait. It may be quite flexible in the face of ecological constraints and challenges, as there seems to be convergent evolution when different types of calls are mapped onto the molecular phylogenies.

1. Now I just read comics.

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