Blond Melanesians: what else are we missing?

05 Friday Oct 2012

Posted by sedeer in Evolution, Genetics, Humans

Tags

biology, Blond, diversity, Europeans, Genetics, Genome, Melanesians, Popular science, science, science and society, Science in Society, Solomon Islands

On the Solomon Islands in the south-eastern Pacific, it’s not uncommon to come across Melanesian children with dark skin and remarkably blond hair. While most people might take this unusual trait as a sign of European ancestry, Sean Myles wasn’t convinced. Curious to understand how the darkest skinned people outside of Africa could also have the highest frequency of blond hair outside of Europe, he led a team of scientists to unravel the genetics behind this mystery. The striking results of their research should serve as a note of caution about what we’re learning from the rapidly growing field from human genomics.
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We’ve been wrong about when humans spread out from Africa

14 Friday Sep 2012

Posted by sedeer in Evolution, Genetics, Humans

≈ 7 Comments

Tags

Hominidae, Human, Mitochondrial DNA, Mitochondrial Eve, Mutation rate, Popular science, Radiocarbon dating, science

Most of the interesting recent events in human evolution probably happened longer ago than we had thought, according to Aylwyn Scally and Richard Durbin of the Sanger Institute. In an opinion piece published in Nature Review Genetics this week, they re-examine the story of how humans left Africa, taking into account new data from several recent whole-genome studies.

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Debating our ancestors’ sex life

05 Wednesday Sep 2012

Posted by sedeer in Evolution, Humans

≈ 9 Comments

Tags

biology, Denisova hominin, Denisovan, DNA, Evolutionary Anthropology, Genome, Homo floresiensis, Human, Neandertal, Neanderthal, Popular science, science

Around 60,000 years ago, modern humans left Africa, the cradle of our species. As we spread across the face of the Earth, we discovered that we weren’t the first or the only humans to make that sojourn. From Central Asia to Europe, we met our distant cousins the Neanderthals, descendants of a 500,000 year old migration; further east were the Denisovans, ranging from Sibera to Southeast Asia. Although these other humans died out around 30,000 years ago, some comfort can be found in the knowledge that a part of them lives on in us. Genetic evidence uncovered in the past few years suggests that our migrating ancestors may have mated with these other humans during their encounters. Not everyone was convinced, though, launching an ongoing debate about whether the genetic similarity might be due to common ancestry rather than inbreeding. Continue reading →

Natural selection: selfish genes & emergent properties

09 Monday Apr 2012

Posted by sedeer in Evolution, Natural Selection

≈ 8 Comments

Tags

altruism, biology, emergence, emergent properties, Gene, Gene-centered view of evolution, Group selection, macroevolution, Popular science, Richard Dawkins, science, selfish gene, Stephen Jay Gould

I briefly mentioned “gene centred views of evolution” in the final paragraph of my previous post in this series about natural selection. In this post, I’d like to expand a bit on the “selfish gene”, which has proven to be quite a powerful idea, and to present my thoughts on why it nevertheless provides an incomplete view of evolution. I know this can be a controversial subject, so feel free to chime in and start a discussion in the comments.

Earlier posts in this series: Modes of selection, Sexual selection, On fitness.

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Mammals didn’t have to wait for the dinosaurs to die out

24 Saturday Mar 2012

Posted by sedeer in Dinosaurs, Evolution, Mammals

≈ 1 Comment

Tags

adaptive radiation, animals, Cretaceous–Tertiary extinction event, dinosaur, diversity, mammal, Popular science, teeth

A study recently published in Nature challenges the prevailing wisdom that the extinction of the dinosaurs paved the way for an explosion of mammalian diversity. By studying the fossils of a group of mammals called multituberculates, the researchers have cast doubt on the traditional view of dinosaurs constraining small, shrew-like mammals to a secondary role as nocturnal insectivores. Instead, this group seems to have diversified millions of years before the dinosaurs died out.
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Natural selection: On fitness

20 Tuesday Mar 2012

Posted by sedeer in Evolution, Natural Selection

≈ 6 Comments

Tags

biology, Darwinism, Education, evolution, fitness, natural selection, Popular science, replicator, science, selfish gene, tautology

For the third part in my series about natural selection I’d like to address the concept of fitness. Thanks to the phrase “survival of the fittest”, fitness is quite a prominent idea in the popular perception of evolution. It was originally coined by Herbert Spencer after he read On the Origin of Species; Darwin adopted the phrase in later editions and it’s been popular ever since. Unfortunately, this glib phrase has often eclipsed a more accurate depiction of evolution, leading to some common misunderstandings. This confusion arises because “fitness” has a different meaning in evolutionary biology than it does in general usage. (Have a look at the earlier posts in this series if you haven’t already read them; the first was about the different modes of natural selection and the second discussed selection mechanisms, focusing on sexual selection in particular.)

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