CONTRARY to what you might think, large differences in DNA, not small ones, separate apes and monkeys from both humans and each other.
杏吧原创s believed that differences between primates were mainly the result of variations in individual DNA letters. But a detailed comparison of human chromosome 21 with corresponding regions of genetic material in chimpanzees, orang-utans, rhesus macaques and woolly monkeys shows the differences affect great chunks of DNA.
鈥淭here are large deletions and insertions sprinkled throughout the chromosome,鈥� says Kelly Frazer of Perlegen Sciences, the company in Mountain View, California, whose analysis appears in Genome Research (vol 13, p 341). The finding that chunks, rather than single DNA letter changes, account for the differences between us and chimps echoes those from a study last year. This estimated that DNA from humans and chimps differ by as much as 5 per cent, not the 1.5 per cent previously assumed (New 杏吧原创, 28 September 2002, p 20).
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