From chimps to chickens: how a little DNA can make a lot of difference

06 Sunday Jan 2013

Posted by sedeer in Development, Evolution, Genetics

Tags

alternative splicing, animals, biology, DNA, Gene, Genome, mammal, Messenger RNA, Popular science, RNA sequencing, RNA splicing, science, Species, Transcriptome, vertebrate

Humans and chimpanzees famously share more than 98% of their genome and yet the two species look and behave quite differently. This apparent paradox stretches well beyond our little corner of the tree of life; we share more than half our genes with chickens and those we share are 75% identical. Two studies published together in the December issue of Science tackled this perplexing discrepancy by showing that there may be more to a genome than meets the eye. Continue reading →

Do ants really count their steps?

09 Friday Nov 2012

Posted by sedeer in Arthropods, Humans, Hymenoptera, Mind

≈ 65 Comments

Tags

animals, ants, Behavior, biology, Cognition, Human, Insecta, Popular science, science, Science in Society

Several years ago, scientists published an excellent study about how desert ants find their way home after foraging. The story got a lot of media attention; unfortunately, much of the coverage described the ants “counting steps”, which isn’t what the researchers reported and feeds into existing myths rather than broadening our scope. To explain what I think is wrong with that approach, I’m going to tell you a story about ants on stilts, body swapping and how we perceive space. Continue reading →

Telling left from right: which side gets the heart?

23 Tuesday Oct 2012

Posted by sedeer in Development, Evolution, Form, Genetics, Vertebrates

≈ 3 Comments

Tags

animals, biology, Cytoskeleton, emergence, Popular science, science, shape, symmetry, Tubulin

This was originally a guest post on The Trenches of Discovery. Thanks, Shaun!

One out of every 8,000 humans is born with some of their internal organs on the wrong side of their body, a condition which can have serious medical consequences. Although we’re usually described as symmetric, that’s only superficially true. Like other vertebrates, we look symmetric from the outside but our internal organs show left-right asymmetry; unless you happen to be a Time Lord, you have only one heart which is normally located on the left side of your chest. Changes to the organization of the internal organs can lead to cardiac defects, misalignment of the bowel and other serious problems. Many genes are known to play a role in establishing this asymmetry, but we still don’t fully understand its evolutionary and developmental origins. Earlier this year, a paper published in the journal PNAS described how this asymmetry is established by subcellular components early in embryonic development.

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What did we actually learn about GM foods and tumors?

26 Wednesday Sep 2012

Posted by sedeer in Genetics, Mammals

≈ 8 Comments

Tags

animals, Genetically modified food, Genetically modified maize, GMO, Monsanto, Popular science, Roundup, science, science and society, Science communication, Science in Society, Statistics

There’s been a great furor recently about a study which purports to show that rats fed GM corn develop more tumors than rats fed regular corn. I’m actually a bit late to this party; scientists and science writers across the web have already picked apart the flaws in this study, from shoddy statistics to poor design, and Carl Zimmer has called the whole thing “a rancid, corrupt way to report about science“. I don’t have much to add to the chorus; what I’d like to do with this post is to make clear to the layperson what we mean by “bad statistics” and why that makes the study unconvincing.

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How does an ant colony coordinate its behaviour?

28 Tuesday Aug 2012

Posted by sedeer in Complex systems, Hymenoptera, Insects, Modelling

≈ 53 Comments

Tags

animals, anternet, ants, Behavior, biology, complexity, emergence, emergent behavior, internet, network, Popular science, science

A recent study looking at how colonies of ants regulate their foraging behaviour has caused a bit of a buzz online. A lot of the coverage has focused on a similarity highlighted in the press release, which says that the ants “determine how many foragers to send out of the nest in much the same way that Internet protocols discover how much bandwidth is available for the transfer of data”. While it’s wonderful that the study has received so much attention, I can’t help but feel that the really interesting aspect of this study has been overlooked in the excitement about the “anternet”. While the similarity between the two systems is striking, I’m more fascinated by a basic difference: unlike our computer networks, the regulation system in ants isn’t purposefully designed but emerges from uncoordinated decisions made by individuals.
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We still don’t know how birds navigate

17 Tuesday Apr 2012

Posted by sedeer in Birds

≈ 3 Comments

Tags

animals, biology, bird, migration, navigation, Popular science, science

Everyone knows that migrating birds are capable of incredible feats of navigation; for example, the Bar-tailed Godwit manages to navigate across the Pacific during its non-stop 11,000km flight from Alaska to New Zealand. Some birds use visual or olfactory cues to navigate, but many birds are able to sense the Earth’s magnetic field, an ability which is supposed to be underpinned by a group of iron-rich cells in the upper beak. However, a study just published in Nature has uncovered the true identity of these cells and shown that they’re probably not involved in sensing magnetism, re-opening the question of how birds can navigate across thousands of kilometers.
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