Ultrasound Video Captures Fetuses Yawning … Why Do They Do It? Yawning is a behavior that everyone is aware of, and we all take part in it, yet no one knows the precise reason why we do it. There’s a ton of theories: A need to rapidly get oxygen into the blood, a way to remain alert for possible danger, imbalances in neurotransmitter levels, and even regulating brain temperature. None of them have been completely proven right or wrong. The social aspect of yawning is much better understood. It is likely a way for social animals to synchronize their mood and sleep schedules, as well as communicate empathy. Of course, a fetus can’t communicate with anyone (except via kicking), so why would they need to yawn? New research (check out the paper in PLOS One) suggests that it could be part of brain maturation. As the fetal brain develops, the neural cycles that will later become sleep and wakefulness are kicking in. It could even be as simple as a way to exercise the jaw movements that will later be necessary in nursing and crying. Whatever the reason, we now have visual proof of certifiable yawns kicking in long before birth, and it’s kind of freaky looking. More research (in adults, children and prenatal infants) will be needed to get at the “why”. By the way, if you yawned while reading this, you aren’t alone. About 60% of people reading or thinking about yawning will yawn. (GIF adapted from video by Wolfgang Moroder)
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Ultrasound Video Captures Fetuses Yawning … Why Do They Do It?

Yawning is a behavior that everyone is aware of, and we all take part in it, yet no one knows the precise reason why we do it. There’s a ton of theories: A need to rapidly get oxygen into the blood, a way to remain alert for possible danger, imbalances in neurotransmitter levels, and even regulating brain temperature. None of them have been completely proven right or wrong.

The social aspect of yawning is much better understood. It is likely a way for social animals to synchronize their mood and sleep schedules, as well as communicate empathy. Of course, a fetus can’t communicate with anyone (except via kicking), so why would they need to yawn?

New research (check out the paper in PLOS One) suggests that it could be part of brain maturation. As the fetal brain develops, the neural cycles that will later become sleep and wakefulness are kicking in. It could even be as simple as a way to exercise the jaw movements that will later be necessary in nursing and crying. Whatever the reason, we now have visual proof of certifiable yawns kicking in long before birth, and it’s kind of freaky looking. More research (in adults, children and prenatal infants) will be needed to get at the “why”.

By the way, if you yawned while reading this, you aren’t alone. About 60% of people reading or thinking about yawning will yawn.

(GIF adapted from video by Wolfgang Moroder)

Viral Conception How the origin of mammals could be written in our genome … by viruses. Every human being starts the same way, with a sperm and egg becoming one, 23 chromosomes from each parent contributing the genetic instructions that will one day make, well … you. But the genes, the actual DNA that writes for proteins, make up only about one one-hundredth of all the DNA in those 46 chromosomes. A full 8% of the DNA in your genome, though, are the remains of ancient viruses. A certain type of virus called a “retrovirus” is capable of inserting its genome into its host, literally writing itself into your DNA. This is the family that HIV belongs to. If a retrovirus infects an egg and inserts its genome, it can get passed down to the next generation. We are full of these remnants, as inactive but still recognizable fossils of past infections. Dr. Samuel Pfaff and his team were trying to come up with a list of genes that were turned on in a developing mouse embryo, just after sperm and egg had come together. In its earliest stages, an embryo’s cells can become any tissue (one of the ideas behind stem cell therapies). What genes make this possible? It turns out that for over 100 genes, the switches (called “promoters”) that turned them on came from a very unlikely place: viruses. WHAT?! We know that these genes must be activated in order for an embryo to correctly develop, but the switches that control them come from ancient viral infections! The genes themselves? Purely mouse.  What an odd paradox of evolution!! We need these genes on at a very precise moment, and off a short while after that. If any of it goes wrong, no baby mouse. So evolution selects these viral sequences to be the control mechanism. Could an ancient infection have been the key to the very existence of mammals? Carl Zimmer has more at The Loom.
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Viral Conception

How the origin of mammals could be written in our genome … by viruses.

Every human being starts the same way, with a sperm and egg becoming one, 23 chromosomes from each parent contributing the genetic instructions that will one day make, well … you. But the genes, the actual DNA that writes for proteins, make up only about one one-hundredth of all the DNA in those 46 chromosomes.

A full 8% of the DNA in your genome, though, are the remains of ancient viruses. A certain type of virus called a “retrovirus” is capable of inserting its genome into its host, literally writing itself into your DNA. This is the family that HIV belongs to. If a retrovirus infects an egg and inserts its genome, it can get passed down to the next generation. We are full of these remnants, as inactive but still recognizable fossils of past infections.

Dr. Samuel Pfaff and his team were trying to come up with a list of genes that were turned on in a developing mouse embryo, just after sperm and egg had come together. In its earliest stages, an embryo’s cells can become any tissue (one of the ideas behind stem cell therapies). What genes make this possible?

It turns out that for over 100 genes, the switches (called “promoters”) that turned them on came from a very unlikely place: viruses. WHAT?! We know that these genes must be activated in order for an embryo to correctly develop, but the switches that control them come from ancient viral infections! The genes themselves? Purely mouse. 

What an odd paradox of evolution!! We need these genes on at a very precise moment, and off a short while after that. If any of it goes wrong, no baby mouse. So evolution selects these viral sequences to be the control mechanism. Could an ancient infection have been the key to the very existence of mammals?

Carl Zimmer has more at The Loom.

Source: blogs.discovermagazine.com