Words or phrases from one paragraph repeated at the start
of the next explicitly tie the two together.
Only 3,100 surnames are now in use in China, say researchers,
compared with nearly 12,000 in the past. An "evolutionary dwindling"
of surnames is common to all societies, according to Du Ruofu of the
Chinese Academy of Sciences; but in China, he says, where surnames have
been in use far longer than in most other places, the paucity has
become acute.
To get an idea of just how acute, imagine that
the combined populations of the United States and Japan had to make
do with but five surnames. That, essentially, is how things are in China,
where the five most common surnames—Li, Wang, Zhang, Liu, and Chen—are
shared by no fewer than 350 million people. Those named Li alone number
87 million, nearly 8% of the country's Han people, the ethnic Chinese.
Another 19 surnames each cover 1% or more of the population.
So far, RNA editing has been seen in marsupials, protozoa,
slime moulds, ferns, and flowering plants. Flies do it. Mice
do it. And, it now appears, people do it.
Or rather, in most cases, their mitochondria do it.
Mitochondria—the cellular machines where glucose is burned for
energy—are found in all cells more sophisticated than bacteria.
Indeed, many biologists suspect that the ancestors of mitochondria actually
were bacteria which gave up an independent life to live symbiotically
in early complex cells. They have their own genes, in any case. And
these genes are turning out be heavily edited.
