Science News Update: September 20th


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Toxoplasma Alters the Brains of Mice


image source: Lxowle via Wikimedia Commons

Normally, mice do a fairly good job of avoiding this fate. That is because they can sense cat urine and avoid the area.  However, mice with the Toxoplasma parasite lose their fear of cats, which increases their chances of becoming dinner.

How does this happen? The parasite changes the brain of the mice so that they lose their fear of cat urine. By doing so, the parasite increases the chances (for up to 4 months) that the mice will be eaten by the cat. Like many parasites, Taxoplasma needs multiple hosts to complete its life cycle, and its final host is the intestinal track of a cat!


Handedness has a Genetic Basis

Are you left or right-handed? If you are left-handed we now know that this isn’t because of brain damage before you are born, or the work of the devil, but rather a variation in the gene called PCSK6. PCSK6 is involved with establishing body symmetry during embryonic development. Variations in this gene are associated with left and right-handedness, but the exact mechanisms remain unclear. There isn’t a strictly genetic, as both genetic and environmental factors have an influence.



“The enemy of my enemy is my friend”.

Such is the case for the peaceful leaf-cutting ants. These ants have 2 enemies – invading parties of competing ants, and another species that produces toxins. However, by inviting some of the toxin-producing ants into their homes, the leaf-cutting ants are able to set up a chemical defensive barrier that repels the conquering ant species.

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Editor’s Picks

Blueberries and Red Grapes Enhance the Immune System

More reasons to get blueberries and red grapes into your diet. Compounds in blueberries (pterostilbene) and resveratrol in red grapes have been shown to work with vitamin D in the body to enhance the innate immune responses. The innate responses are the general defense mechanisms of the body, and provide a background protection against pathogens.


An Interactive Timeline of Genetic Discoveries

This is a great interactive timeline of the major investigators and discoveries in the history of genetics.


Your Genome May Not be Your Own

Our ability to rapidly analyze genomes is producing some interesting findings. Namely, the idea that many of us may harbor multiple genomes in our bodies. This article by Carl Zimmer does an excellent job of describing chimeras and mosaics, and some of the potential consequences of these findings.


Video of the Week

We are going to be a little selfish and feature another one of our own videos this week.  We have been producing these videos to help students understand some of the more difficult concepts in biology, and provide instructors with materials that they can use both in the classroom and for remedial work.

This week’s video is on X-inactivation and dosage compensation. A follow-up video on the effects of X-inactivation on calico cats is in the works. Check our video page for updates and links to our new Vimeo channel.

X inactivation from Ricochet Science on Vimeo.

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