It sounds like exciting science: the hunt for the genes that make us human. But are we learning all that much about our biology by tracking down those parts of our genome that are unique to us?
In my Pacific Standard column this week, I argue no – at least not yet. The search for human specific genes, or those parts of our genome that show signs of rapid evolution, called “human accelerated regions” hasn’t really yielded much insight into what makes us different from other species, particularly our closest relatives. For the most part, we’ve discovered genes and regulatory elements that are somehow associated with brain function, but we can’t say much more than that. Continue reading
Ecclesiastes 9:11 contains a very poetic description of genetic drift as a mechanism of evolution, though it leaves out any description of the importance of effective population size:
I returned, and saw under the sun, that the race is not to the swift, nor the battle to the strong, neither yet bread to the wise, nor yet riches to men of understanding, nor yet favour to men of skill; but time and chance happeneth to them all.
-King James Version
Photo Credit: Jennifer Taylor (All Rights Reserved; Used with Permission)
You are never to young for a meta-costume*.
To the untrained eye, it may look like my daughter is dressed as a monarch butterfly for Halloween. To the trained eye, you will recognize that half of her parental set is extremely dorky.
She is actually going as the concept of Müllerian Mimicry instantiated in the form of a viceroy butterfly. This costume is occassionally mistaken for Batesian Mimicry by novices.
Butterfly (monarch) on a Penta by Arturo Yee (CC BY 2.0)
Viceroy by Rodney Campbell (CC BY 2.0)
Suggestions that we need a new evolutionary synthesis because of phenomenon X pop up like weeds in biology. It’s nice to see some of my favorite evolutionary geneticists – Greg Wray, Hopi Hoekstra, Douglas Futuyma, Richard Lenski, Trudy Mackay, Dolph Schluter and Joan Strassman – make a strong case that the fundamentals of evolutionary theory can accommodate the hot new phenomenon of the day (e.g, epigenetics), and that genes are not passé:
The evolutionary phenomena championed by Laland and colleagues are already well integrated into evolutionary biology, where they have long provided useful insights. Indeed, all of these concepts date back to Darwin himself, as exemplified by his analysis of the feedback that occurred as earthworms became adapted to their life in soil…
Finally, diluting what Laland and colleagues deride as a ‘gene-centric’ view would de-emphasize the most powerfully predictive, broadly applicable and empirically validated component of evolutionary theory. Changes in the hereditary material are an essential part of adaptation and speciation. The precise genetic basis for countless adaptations has been documented in detail, ranging from antibiotic resistance in bacteria to camouflage coloration in deer mice, to lactose tolerance in humans…
All four phenomena that Laland and colleagues promote are ‘add-ons’ to the basic processes that produce evolutionary change: natural selection, drift, mutation, recombination and gene flow. None of these additions is essential for evolution, but they can alter the process under certain circumstances. For this reason they are eminently worthy of study.
h/t Ed Yong
On 11 August 2014, Michael R. Gillings published a paper in Evolutionary Applications entitled “Were there evolutionary advantages to premenstrual syndrome?” There is a strain of thinking that is common in the general public, but is also frequently found among academic researchers that I call adaptionism. This line of thinking assumes that, if a biological phenomenon exists, it must be there as the result of natural selection – i.e., be adaptive. This makes things like PMS seem like a great, evolutionary mystery to be “solved”.
Premenstrual syndrome (PMS) affects up to 80% of women, often leading to significant personal, social and economic costs. When apparently maladaptive states are widespread, they sometimes confer a hidden advantage, or did so in our evolutionary past. –from the abstract, Matthew R. Gillings (DOI: 10.1111/eva.12190)
I could spend pages on the problems with this approach to such a question. Fortunately for you and I, Kathryn Clancy, who is far more knowledgable on the relevant evolutionary anthropology than you and I, gutted this paper for The Daily Beast earlier this week:
…the fact that PMS is heritable and variable tells us nothing about whether women with PMS have more children than those who don’t, and this is the true test for adaptation. This crucial point—the third and most crucial condition for natural selection—is absent from the paper.