Doubling Up

Our big brains may be the result of a doubled gene that lets brain cells migrate to new areas, says a new study. The gene, known as SRGAP2, has been duplicated in our genomes at least twice in the four million years since our ancestors diverged from those of the other great apes. It codes for a certain protein that interferes with filopodia – tiny molecular structures that shape the growth of neurons in a developing brain. Researchers think that as SRGAP’s protein disrupted the “normal” growth of our ancestors’ filopodia, millions of their neurons migrated outward to thicken the cerebral cortex – … Continue reading Doubling Up

Autistic Genetics

Some forms of autism seem to be linked with variations in certain genes, a new study says. The deletion of a certain cluster of 27 genes on the mammalian chromosome 16 – specifically a region known as 16p11.2 – causes autism-like features to develop in mouse brains. These mice exhibited hyperactivity, repetitive behaviors, and difficulty adjusting to new environments, much like human children with autism. (As I mention a lot on this blog, mouse brains provide pretty reliable models of certain human brain functions, which is why neuroscientists experiment on them.) The idea that chromosome 16 might be linked to autism dates … Continue reading Autistic Genetics

Enzyme Alarm Clock

Researchers have isolated a protein that sounds our biological clock’s alarm each morning, a new study reports. A gene known as KDM5A codes for an enzyme (i.e., a protein that increases the rate of a chemical reaction) called JARID1a. This enzyme acts as a switch that starts the biochemical process of waking us from sleep – like some kind of weird molecular rooster. Here’s the background: scientists have known for years that levels of a protein called PER rise in the morning and fall toward nighttime. The level of PER in our bodies helps our cells know what time of day it is … Continue reading Enzyme Alarm Clock

Optimistic Genetics

For the first time, scientists have pinpointed a particular gene variation linked with optimism and self-esteem, a new study reports. Two different versions – alleles – of the oxytocin receptor gene (OXTR) exist: an allele with the nucleotide “A” (adenine) at a certain location, and an allele with “G” (guanine) at that same location. Previous studies had found that people with at least one “A” molecule at that location tended to have heightened sensitivity to stress, and worse social skills. But as the journal Proceedings of the National Academy of Sciences (PNAS) reports, a team led by UCLA’s Shelley E. Taylor were able to correlate certain alleles of … Continue reading Optimistic Genetics

Skin Into Brain

Scientists have discovered a way to convert human skin cells into working brain cells. Cue the Weird Science theme song! Using strands of microRNA molecules and a few carefully chosen genes, a team led by Dr. Sheng Ding at the Scripps Research Institute reprogrammed the genetic code of skin cells taken from a 55-year-old patient, transforming them into full-fledged neurons that actually synapse with each other. As the lab’s report in the journal Cell Stem Cell1 explains, this new reprogramming method allows scientists to directly transform one cell type from an adult human into a normal, functional cell of a completely different type: These human induced neurons (hiNs) exhibit … Continue reading Skin Into Brain

Inherited Memory

Scientists have discovered a molecular mechanism by which a parent’s experiences can alter the genes of its children. Several recent studies have demonstrated connections between environmental factors and inherited genetic traits – for instance, people whose parents lived through famine tend to have higher rates of diabetes and heart disease – but this latest research, published in the journal Nature, marks the first hard evidence of such a modification process at work. Before we dive into the details, though, let’s back up a bit, and take a look at why this is such a Big Freakin’ Deal. See, the whole concept of inheritance via … Continue reading Inherited Memory