[单项选择]Though explaining the entire human genetic blueprint is still a few years away, scientists have begun laying claim to the stretches of DNA whose codes they have succeeded in cracking. In recent years researchers have flooded the U.S. Patent and Trademark Office with applications for thousands of genes and gene fragments — and they have stirred a lot of controversy in the process.
The biggest problem with patenting genes is that while scientists have at least a general idea of what specific strands of genetic coding do, often it’s just that — general. Investigators do sometimes succeed in isolating a single, crisp gene with a single known function. Often, however, researchers trying to map genes get no further than marking off fragmentary stretches of DNA that may be thousands of bases in length. These so-called expressed sequence tags may have real genetic information embedded in them, but determining where those fragments are and what their structure is takes more digging. Gene
A. careless
B. expensive
C. unsuspecting
D. hidden

[单项选择] Though explaining the entire human genetic blueprint is still a few years away, scientists have begun laying claim to the stretches of DNA whose codes they have succeeded in cracking. In recent years researchers have flooded the U: S. Patent and Trademark Office with applications for thousands of genes and gene fragments -- and they have stirred a lot of controversy in the process. The biggest problem with patenting genes is that while scientists have at least a general idea of what specific stretches of genetic coding do, often it’’s just that general. Investigators do sometimes succeed in isolating a single, crisp gene with a single known function. Often, however, researchers trying to map genes set no further than marking off fragmentary stretches of DNA that may be thousands of bases in length. These so-called expressed sequence tags may have real genetic information embedded in them, but determining where those fragments are and what their structure is takes more digging. G
A. They’’ are difficult to mark’’ off.
B. They contain unidentified genetic information.
C. They contain the entire human genetic information.
D. They are genes whose specific functions have been identified.