Passage Four

Questions 16 to 20 are based on the flloning passage.

English people are less genetically diverse today than they were in the days of the Vikings, possibly due to two deadly diseases that swept their country centuries ago, a new study says.

The study compared DNA from ancient and modern Englanders and. Found that the country has a smaller gene pool than it did a thousand years ago.

The findings come in contrast to modern England's reputation as a cultural melting pot, where in many major cities you are as likely to hear Urdu from India or Yoruba from Nigeria being spoken on the streets as English.

Rus Hoelzel, a geneticist from the Britain's University of Durham, and his colleagues obtained DNA samples from the skeletal remains of 48 ancient Britons who lived between A.D.300 and 1000. The researchers studied the DNA, which was passed down from mothers to their children. By comparing the DNA with that of thousands of people from various ethnic backgrounds living in England today, they found that genetic diversity was greater in the ancient population. The team also compared the ancient DNA with samples from people living in continental Europe and the Middle East, and found a similar lack of genetic variety.

One possible explanation for this narrowing of diversity might be two major outbreaks of plague that swept England and much of Europe -- the Black Death (1347 1351) and the Great Plague (1665 66).

The Black Death epidemic is estimated to have killed as much as 50 percent of the population of Europe. Three centuries later, a fifth of the population of London died in the Great Plague. However, these diseases didn't kill randomly, Hoelzel explained. The plague killed some people while others remained resistant, he said.

Eske Willerslev, a specialist in ancient DNA from the University of Copenhagen, said he is surprised by the findings but agrees that the historic epidemics may explain the loss in diversity.

Since. the diseases, it appears that England hasn't been able to make up the loss to the gene pool, despite the high rate of immigration into the country over the past 200 years.

The modem England's reputation as a cultural melting pot (Para. 3) most probably mean     s.