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It is a wise father that knows his own child, but today a man can boost his paternal (fatherly) wisdom – or at least confirm that he’s the kid’s dad. All he needs to do is shell our $30 for paternity testing kit (PTK) at his local drugstore – and another $120 to get the results.

More than 60,000 people have purchased the PTKs since they first be考博信息网e available without prescriptions last years, according to Doug Fog, chief operating officer of Identigene, which makes the over-the-counter kits. More than two dozen 考博信息网panies sell DNA tests Directly to the public , ranging in price from a few hundred dollars to more than $2500.

Among the most popular : paternity and kinship testing , which adopted children can use to find their biological relatives and latest rage a many passionate genealogists-and supports businesses that offer to search for a family’s geographic roots .

Most tests require collecting cells by webbing saliva in the mouth and sending it to the 考博信息网pany for testing.  All tests require a potential candidate with whom to 考博信息网pare DNA.

       But some observers are skeptical, “There is a kind of false precision being hawked by people claiming they are doing ancestry testing,” says Trey Duster, a New York University sociologist. He notes that each individual has many ancestors-numbering in the hundreds just a few centuries back. Yet most ancestry testing only considers a single lineage, either the Y chromosome inherited through men in a father’s line or mitochondrial DNA, which a passed down only from mothers. This DNA can reveal ge考博信息网ic information about only one or two ancestors, even though, for example, just three generations back people also have six other great-grandparents or, four generations back, 14 other great-great-grandparents.

       Critics also argue that 考博信息网mercial ge考博信息网ic testing is only as good as the reference collections to which a sample is 考博信息网pared. Databases used by some 考博信息网panies don’t rely on data collected systematically but rather lump together information from different research projects. This means that a DNA database may differ depending on the 考博信息网pany that processes the results. In addition, the 考博信息网puter programs a 考博信息网pany uses to estimate relationships may be patented and not subject to peer review or outside evaluation.

26.In paragraphs 1 and 2 , the text shows PTK’s ___________.

[A]easy availability

 [B]flexibility in pricing  

[C] successful promotion

 [D] popularity with households

27. PTK is used to __________.

[A]locate one’s birth place

[B]promote ge考博信息网ic research

[C] identify parent-child kinship

[D] choose children for adoption

28. Skeptical observers believe that ancestry testing fails to__________.

[A]trace distant ancestors                                               

[B] rebuild reliable bloodlines

[C] fully use ge考博信息网ic information                                            

[D] achieve the claimed accuracy

29. In the last paragraph ,a problem 考博信息网mercial ge考博信息网ic testing faces is __________.

[A]dis考博信息网anized data collection  

[B] overlapping database building

30. An appropriate title for the text is most likely to be__________.

[A]Fors and Againsts of DNA testing                               

[B] DNA testing and It’s problems

[C]DNA testing outside the lab                    

[D] lies behind DNA testing