BBC 6分钟英语 你可以相信血统DNA试剂盒吗

6 min English from BBC Learning english com.

Hello. This is 6 min English from BBC Learning English.

I'm Neil, and I'm Beth. Nowadays, it's

popular to find out more about your family history by tracing your family tree, a diagram

that shows all the members of a family over

a long period of time. What do you know about your family history best?

Well, my mom actually did our family tree, um.

She found a lot of our ancestors had emigrated to the United States.

Yeah, I don't know much more than that.

What about you? Well, I'm lucky to have an unusual surname, so it quite easy to trace my ancestors.

And somebody in my family has, uh, gone back to 17 hundred and found somebody with my name.

Wow, that's amazing. Well, the Internet has made it easier to find the historical records needed to research your ancestry, the origins of your family.

But what if you want to find out about a time before historical records began?

Luckily, some companies now offer to trace your ancestry using DNA.

DNA is the cellular information that's passed down from paren'ts to children, telling the body how to create life.

Listener Chris from the UK recently took a DNA ancestry test.

When the test returned some unexpected results.

Chris called BBC radio four program sliced bread, wondering how accurate they really were.

Not so long ago, I sent off a home DNA testing kit, and the results that came back were broadly in line with expectations, but they had some little glitches in there, which made me think, is this accurate, or is it to be taken with a pinch of salt?

Chris wondered whether his results were accurate, or whether to take them with a pinch of salt, an idiom, meaning to doubt something is completely true.

So in this program, will discuss how accurate DNA ancestry tracing is, and, as usual, will learn some useful new words and phrases.

And remember, you can find all the vocabulary for this program on our website, bbc learning english dot com.

1st though, I have a question for you, beth.

One reason to be cautious about DNA ancestry tests is that humans are very similar to each other.

Most of your DNA is identical with every other person on Earth, and it's only the tiny amount of difference that accounts for all genetic variations between humans.

So exactly how much DNA to humans share with each other?

Is it A 79.9 %? B 89.9 %?

Or see 99.9 %? I am going to guess 99.9 %.

Okay, well, we'll find out the answer later in the program.

Another problem for research based on DNA is agreeing on the meaning of words like ancestry and ethnicity.

Here, genealogist Louise Boldoch explains the difference between these words to BBC radio for program Sliced Bread.

So ancestry is really about people.

It's about your actual forbears, your ethnicity.

You would probably think of in geographical terms, maybe which continent or which region your people came from.

Like ancestors, the term forbears means actual people, the relatives in your family from a long time ago.

But Louise is more interested in the term ethnicity, the shared culture, language and traditions of a group of people.

And this is closely connected to a geographical location.

And it's this question of geography which interested BBC Presenter Greg Foot Gregg sent DNA samples to two different companies.

The results from the 1st company matched what he already knew about his family, that the past five generations came from England.

But listen to what happens when Louise Boldoch revealed the results of gregg's 2nd DNA test on his BBC Radio four show Sliced Bread.

He's gonna blow your mind. Okay, can I tell you what you're looking at?

Yes, please do. It says that you are 1st of all 66% North and West Europe, but explicitly, that doesn't refer to the United Kingdom.

It's a wide geographic area, 27 and a half percent Irish, scottishham Welsh, but again, explicitly of not English.

The 2nd companies DNA test blows gregg's mind.

It makes him very excited and surprised.

There's no evidence of his ancestors being English at all.

Actually, companies compared DNA with other samples in their database, and since companies use different databases, it's not too surprising that greg's results were so different, unlike his actual DNA.

Speaking of which, what was the answer to your

question? Neil, I asked you what percentage of human DNA is shared by everyone?

And what was your answer? Beth?

I said, 99.9 %.

Well, you must be very clever, because the answer is correct.

Well done,

right? Let's recap the vocabulary we've learned,

starting with family tree diagram showing all the members of a family.

Ancestry refers to the origins of the family.

If you take something with a pinch of salt, you don't believe it's completely true.

Forbears are relatives who lived in the past.

Ethnicity means the social, cultural and linguistic characteristics are shared by a group of people.

And finally, if something blows your mind, it makes you excited or surprise.

Once again, our 6 min are up.

But why not head over to the BBC Learning English website?

Well, you'll find a worksheet and quiz especially for this program.

See there. Soon. Goodbye, from bbc learning english dot com.

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