专题限时训练(三十七) [科普知识型阅读理解(一)]
(限时：25分钟)
(一)
DNA left at a crime scene could be used in the future to build up a picture of an offender's face, which was revealed tonight.
A first step towards genetic mugshots has been taken by researchers in the US who link specific DNA markers with face shapes. To identify the genes, they focused on known mutations(突变) that cause changes of the face and head. Normal versions of these genes were found to influence individual features. For instance, one gene affected the lips, another the shape and configuration of bones around the eyes, and a third the appearance of the midface and skull. In total, 20 genes had “significant effects” on facial appearance.
Lead scientist Professor Mark Shriver, from the Pennsylvania State University, said, “We use DNA to match to an individual or identify an individual, but we can get so much more from DNA. Currently we can't go from DNA to a face, or from a face to DNA, but it should be possible.” The implications are farreaching, raising the possibility of creating a data bank of facial types based on genetic markers. DNA from a crime scene could then be used to produce a rough image of the face of an offender or victim. Such genetic mugshots may be more reliable than computergenerated “Efits” based on witnesses' memory. Other uses of the technique might include proving the identities of fathers in paternity cases, or visualizing our remote ancestors from fossil DNA.
The scientists wrote in the online journal Public Library of Science Genetics，“Such predictive modelling could be forensically useful. For example, DNA left at crime scenes could be tested and faces could be predicted in order to help to narrow the pool of potential suspects. Further, our methods could be used to predict the facial features of descendants, deceased ancestors, and even extinct human species. In addition, these methods could prove to be useful diagnostic tools.” The team developed a model which first established a range of physical face shapes from people of mixed West African and European ancestry from the US, Brazil and Cape Verde. Measurements were taken of thousands of point coordinates on grids placed over 3D images of the faces.
Statistical methods were then used to determine the relationship between facial differences and the effects of genders, ethnic ancestry and individual gene variants.
1．The underlined word “mugshots” in the second paragraph most probably means “________”．
A．different faces B．characteristics
C．pictures of faces D．genders
