【单选题】

The idea that people might be chosen or rejected for jobs on the basis of their genes disturbs many. Such (1) may, however, be a step (2) , thanks to work just published inCurrentBiology byDerk-JanDijk and his colleagues at the University of Surrey, inEnglan

D、Dr.Dijk studies the biology of time-keeping—in particular of the part of the internal body-clock that (3) people to sleep and wakes them up. One of the genes involved in (4) this clock is known as PER3 and (5) in two forms.Dr.Dijk’s work (6) that one of these forms is more conducive to night-shift work than the other.
The two forms of PER3 (7) into two slightly different proteins, one of which is longer than the other. (8) work by this group showed that people with two short versions of the gene are more likely to be "owls", (9) to get up late and go to bed late. "Larks"— (10) , early risers, have two long versions. Pursuing this (11) of enquiry,Dr.Dijk and his team have been studying how such people (12) to sleep deprivation. Two dozen volunteers, some genetic owls and some genetic larks, were forced to stay awake for two days. The genetic larks reacted to this worse than the owls di
D、 (13) , larks given memory tests and puzzles to (14) between the hours of four and eight in the morning turned (15) far worse performances than did owls.
What (16) that may have for employers is not fully clear. Nevertheless, it is intriguing. There may (17) come a time when employers (18) night shifts will want a blood sample from (19) employees— (20) to protect themselves against negligence suits should someone have an accident.
A、falls B、lies C、comes
D、consists