Understanding the human body is a team effort. That's where the Yachtel group comes in.

Researchers at Yachtolt have been delving into the secrets of probiotics for 90 years.

Yacold also partners with nature portfolio to advance gut microbiome science through the global grants for gut health, an investigator-led research program.

To learn more about Yachtolt, visit yawcult.co.

.jp. That's Y-A-K-U-L-T.C-O.J-P. When it comes to a guide for your gut, count on Yacult.

This is Scientific Americans' 60-second Science. I'm Karen Hopkins.

Why did the chicken cross the road? Well, that's a philosophical pickle. But if you want to know why chickens don't get cross at people, why they're content being kept in their coops, science can help.

Domestic species are interesting because their genetic makeup has changed

dramatically as part of the process of going from wild to domestic. Lisa Lugge, an evolutionary

geneticist and anthropologist at the universities of Oxford and Cambridge. And indeed when people

have compared modern domestic animals with their wild relatives, they've identified genes that do

show signs of strong reason selection.

One such gene is thyroid-stimulating hormone receptor, otherwise known as TSHR.

In chickens, a variant of this gene that is widespread in modern populations has been shown

to directly cause chickens to be less

fearful of humans and also result in reduced aggression towards con-specifics.

But when exactly did the selection for these traits, and therefore this variant, take place?

It's been suggested because of the potential usefulness of these traits in domestic setting,

that selection on this gene must have happened when chickens were first domesticated around 6,000 years ago in East Asia.

But in an evolutionary time scale, this is just a blink of an eye, and we just don't know,

and don't have the resolution to tell when exactly between 6,000 years ago and now this

selection happened, using data from only modern chicken populations. But with DNA from archeological

...