Youtube daily report Aug 3 2018

[♪ INTRO ]

23 pairs.

With just those two words, you probably already know what I'm talking about: chromosomes,

the tightly-wound packets of DNA and protein that together make up our genomes.

And not just any chromosomes, but the number of chromosomes in most humans.

But have you ever thought about why it's 23?

There's a whole range of numbers of chromosomes different species can have.

And scientists have been puzzling over the possible advantages of having more of them for a while.

Weirdly, this number that most of us have memorized may not be as integral as we thought.

Because in papers published in the journal Nature this week, two separate groups of biologists

reported fusing entire sets of chromosomes together, reducing the count down to just one or two.

And, kind of shockingly, things mostly went okay.

Before you start freaking out, this experiment wasn't done in humans.

Instead, the researchers worked with Saccharomyces cerevisiae, a fungus better known as Baker's

or Brewer's yeast, since it's the species we use to make bread and beer.

This yeast normally has 16 chromosomes.

But thanks to genetic engineering technologies, including CRISPR, the scientists were able

to progressively stitch together more and more chromosomes.

That required taking out two structural components of the chromosomes:

centromeres, short DNA sequences roughly in the middle of each chromosome where they attach

to each other during cell division;

and telomeres, the repetitive sequences at the ends of chromosomes that help keep them intact.

You only want one centromere and two telomeres per chromosome, so both groups hacked away

at all the extras, and took slightly different approaches to the fusion part.

One team from China was able to pack all 16 into one single, giant chromosome, while an

American team got it down to just two big chromosomes.

Importantly, the researchers made very few changes to the overall DNA sequence, so any

observed differences are almost certainly a result of messing with the chromosomal structure.

It's actually the first time biologists have ever been able to whittle the chromosome

number down to one in any eukaryote which are organisms like us, whose chromosomes are

stored in a special nucleus compartment in their cells.

So, what happened after this radical change?

At first glance, not much.

No word on what they tasted like compared to the strains we use for bread and beer,

but the chromosome-tinkered strains of yeast looked very much like their normal counterpart in size and shape.

They also went through cell division normally, and it could grow under a variety of conditions.

Yeast geneticists like to test out different nutrients and conditions to see if strains are lacking in certain areas.

And except for slightly slower growth and higher susceptibility to an antifungal compound,

the fewer-chromosome strains did pretty well.

Now, let's pause here for a second, because this alone is kind of astounding.

Scientists can totally rearrange how an organism packages its DNA at a fundamental level, and

at least for yeast, it's totally viable.

Even more shocking to the scientists was that the modified yeasts hadn't really changed

the types of genes that get turned on or off.

Both groups found very few changes compared to regular yeast.

In fact, in the single-chromosome yeast, just 28 genes had substantially changed expression.

That's less than half a percent of all the protein-coding genes!

This is pretty surprising because biologists have long known that the 3D structure of chromosomes

can affect the types of genes that are expressed, and ultimately which proteins are made.

In this case, basically all of the interactions between chromosomes had been obliterated.

But a good chunk of the interactions within the chromosomes remained intact, and those

at the gene level were largely preserved.

This seems to have been enough to keep the yeasts doing their regular thing.

Still, it's not all rainbows and butterflies for the giant chromosome yeasts.

Both teams observed reproductive and fitness deficits.

When grown together with 16-chromosome yeast, the altered yeasts grew more slowly, and in

the case of the single chromosome, was quickly out-competed.

The single-chromosome yeast could successfully mate with itself, but those daughter cells

were slower-growing and occasionally had trouble maintaining the correct chromosome number.

The daughter cells also produced fewer sex cells, and had trouble reproducing.

These differences begin to explain why having a larger number of smaller chromosomes might be a good thing.

For one thing, it might be hard for cells to properly replicate such abnormally large

chromosomes, and then pull the two copies apart correctly.

More chromosomes might also offer more flexibility that could prove useful in the course of evolution.

If you have more chromosomes, it's a little easier to drop one or gain one, which might

give you a better ability to adapt to things like changes in your environment.

Of course, a major change to your genome like that might also be really bad.

It's a bit of a trade-off.

But in the long run, this versatility could provide an evolutionary advantage.

We don't know the exact reasons, but this species of yeast has had 16 chromosomes for

some 10-20 million years.

So something is definitely working.

At the same time, it's now clear that while 16 is the magic number, it's not absolutely critical.

And the same might even be true for us.

Although, it would probably be harder to fuse chromosomes this way in more complex organisms.

That's because they tend to have more complicated DNA sequences around centromeres and telomeres.

So for all we know, we might not be very different if all our chromosomes were fused into one giant one.

But we probably have a little bit more research to do before we can make that happen.

Thanks for watching this episode of SciShow News, and thanks to all of our patrons on

Patreon who help us make videos about amazingly weird science like this every day of the week.

If you wanna support SciShow and get access to cool rewards like our patrons-only questions

inbox, you can check us out at patreon.com/scishow.

[♪ OUTRO ]

For more infomation >> What Happens If You Fuse All Your Chromosomes? | SciShow News - Duration: 5:06.

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Hyundai Trajet 2.0I-16V GLS 25 EDITION 7-PERSOONS - Duration: 1:12.

For more infomation >> Hyundai Trajet 2.0I-16V GLS 25 EDITION 7-PERSOONS - Duration: 1:12.

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GZERO World Clip: Future Education - Duration: 0:36.

We have to completely rethink about what higher education means.

It's no longer about teaching 18-year-olds to go to college, get four-year degrees and

get a job somewhere.

It's about capacitating people with the skills they need for 21st-century jobs which may

or may not be a traditional four-year degree.

And number two, a higher education system capable of retraining people multiple times

throughout their lives so they can quickly adjust.

I think that's the first thing that I think we need to absolutely do, sooner rather than later.

For more infomation >> GZERO World Clip: Future Education - Duration: 0:36.

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Kilometers per Hour to Meters per Second - Conversion - Duration: 2:33.

Hello! My name is Leonardo Sartori and today I am here to

teach you how to convert kilometers per hour to meters per second, and meters per second to kilometers per hour.

To start we are going to convert

seventy two kilometers per hour to meters per second.

Kilometers per hour to meters per second conversion

is quite simple, is just we divide the number by three point six.

I will set up the account here, seventy two

divided by three point six.

Seventy two divided by three point six,

we equate the homes and ignore the point.

Thirty-six times two, seventy two,

zero times thirty-six, zero,

ready. Seventy two divided by three point six

is twenty, so seventy two kilometers per hour

is the same thing that twenty meters per second.

Erase this question mark,

twenty meters per second.

Now the next!

Thirty meters per second to convert to kilometers per hour.

We are going to do the same thing, just the opposite.

Instead of us dividing thirty by three point six,

we are going to multiply the thirty by three point six, the inverse operation.

Three point six times thirty...

Three times six eighteen, up one,

three times three, nine, plus one, ten.

Left the zero,

a house after the point, ready.

Three point six times thirty is a hundred and eight,

so we can say that

thirty meters per second is the same thing as one hundred and eight kilometers per hour.

Now a schema that you can write in your notebook to be simpler to vizualise,

kilometers per hour...

meters per second...

make an arrow...

three point six...

division huh? Here we divide to convert kilometers per hour to meters per second,

and meters per second to kilometers per hour...

three point six...

Or you make a point or you make a multiplication "x".

Ready. You write this on your notebook

or necklace on the wall and you don't forget ever again.

Then that is it, subscribe in the channel

and leave it like, and... thank you!

For more infomation >> Kilometers per Hour to Meters per Second - Conversion - Duration: 2:33.

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Lil Pump x SmokePurpp x Ronnie J Type Beat 2018 | Wrists Prod By Ready2BeamUp - Duration: 3:30.

For more infomation >> Lil Pump x SmokePurpp x Ronnie J Type Beat 2018 | Wrists Prod By Ready2BeamUp - Duration: 3:30.

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Live j essaye d etre gentil mais j arrive pas - Duration: 36:39.

For more infomation >> Live j essaye d etre gentil mais j arrive pas - Duration: 36:39.

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Here's What I Think About the BMW 3 Series and More - Duration: 4:25.

rev up your engines, WI is the awesome, what's your opinion on BMW 318i 2001 143

horsepower, what experience do you have with them, I'm thinking about buying one soon

thank you, okay well if you believe my advice and you think I know

what I'm talking about, don't buy that car they're endless money pits, all BMWs

are, on the other hand if it's cheap enough and you want a toy

I've had people buy those things, what is it now 2001 you're talking about you

know 18 year old car, 2019 just came out so it's an old car, if you could buy one

for a thousand fifteen hundred dollars go ahead and have it as a toy, but don't

expect to use it for an everyday driver, it's just not something you want

to do, they're endless money pits as they age, that cost a fortune to fix the

parts cost a lot, and you often need a special BMW computer to reprogram just

about everything on it, Jonathan zharko says, hey Scotty what do you think

of a 2005 Scion xB, okay those are excellent cars I don't

know why Toyota did that, for a while they made Scions and same company

Toyota made them, but they call them Scions, they're a pretty bulletproof

cars they lasted a long time there are well made cars and now they don't make

them anymore, they just selling them under the Toyota brand again, I guess

they thought, oh we'll sell a whole bunch of these to the young kids, it'll be a new

brand of car, they're kind of silly for doing that, I think they should

have just kept it with Toyota, those are good cars, but any car like

that that's 14 years old, you still want a mechanic like me to check it out

before you buy it, because you can't trust anybody, you don't know if it's

been wrecked, flooded, stolen, and we mechanics can tell them half an hour if

it's got any serious problems by scanning it and driving it around,

JM says, help me I've got a 2013 Ford f-150 and in bumper and bumper traffic it

stays stuck on first gear and the RPM stays stuck until I push on a gas, if I

let go of the gas it keeps going on its own, okay well if you let go of the gas

and keeps going, first thing you want to fix is that, sometimes the throttles just

stick, I got a video make your car run better a little spray cleaner, it shows

how to spray the throttle to get the cleaner in there, so you don't

have to worry about the throttle stick, and pray it's just a sticking throttle

because if you fix that and it doesn't idle high anymore and it still stays

stuck in first gear, then you've got some kind of a transmission problem and those

can be very expensive to fix, but realize that the transmission shifts by data it

gets from the throttle position sensor, so if the throttle sticking it's gonna

make the transmission get weird too, so try cleaning that throttle first, Liberty

City Kelley says, I got a 2001 Pontiac Aztek, I bought it for 1,500 bucks it

makes a clicking sound when I turn the wheel tends to pull to the left, I have

multiple oil leaks in the front too, ok well the first thing you want to do is

fix the clicking noise, that's generally worn CV joints, just jack the car up look

under and look at the inside of each wheel, they have CV joints they have

rubber boots, odds are one of those boots is ripped, the grease is leaked out, then

you just buy a whole CV axle, you don't change the joint because now you can get

aftermarket entire axle assemblies for like 59 bucks for those things and just

replace the whole axle, as for the oil leaks

on those it's usually it's just a valve cover gasket leaking, look at the valve

cover and you see oil under it just change that you, can do it yourself it's a

pretty simple job, Donna cloody, says I got an 88 Chevy

Astro van, should I do a tune-up before replacing the cat, can I wait to do the

tune-up or should I replace the cat first, ok that's kind of a chicken and

the egg question, if your car runs poorly it can trip a code for bad catalytic

converter, so the first thing you always want to do is tune up the car put some

cleaner in it and drive it around a week or so, sometimes if you have an inefficient

cat code it'll go away, now once you tune it up if it still has a problem

with the cat and that's an 88 you're probably gonna need a cat, but at least

it's an old car, so on the old ones you can just have a universal one put on, on the

new ones they're pretty vehicle specific and if

you don't use the correct one that cost a lot of money, it probably won't work

right, but with those older ones you can often put on a universal cat and they'll

work perfectly fine, so if you never want to miss another one

of my new car repair videos, remember to ring that Bell!