Cell Phone Lets YourSecret Out

Your cell phoneholds secrets about you.Besides the names and________(51)that you'ye pro-

grammed intoit,traces of your DNA linger on the device,according to a new study.

DNA is geneticmaterial that_________(52)in every cell.Like your fingerprint, your DNA isunique

to you一_______(53)you have an identicaltwin.Scientists today routinely analyze DNA in blood,

saliva,or hairleft__________(54)at the scene of a crime.The results often help detectivesidentify

________(55)andtheir victims.Your cell phone can reveal more about you ________(56)you might

think.

Meghan J.McFadden,ascientist at McMaster University in Hamilton,Ontario,heard about a crime in

which the suspectbled onto a cell phone and later dropped the_________(57).This made her wonder

whether traces ofDNA lingered on cell phones even when no blood was involved._________(58)sheand

colleague MargaretWallace of the City University of New York analyzed the flip一open phones of 10 volun-

teers.They usedswabs to collect__________( 59)traces of the users from two parts of the phone.the

outside,where theuser holds it,and the_________(60),which is placed at the user's ear.

The scientists scrubbedthe phones using a solution made mostly________(61)alcohol.The aim of

washing was toremove all detectable traces of DNA.The owners got theirphones__________(62)for

another week.Thenthe researchers collected the phones and repeated the swabbing of each phoneonce

more。

The scientistsdiscovered DNA that

_________ (63)to thephone's speaker on each of the phones.

Better samples werecollected from the outside of each phone,but those swabs also picked up DNAthat be-

longed to otherpeople who had apparently also handled the phone.________(64),DNA showed upeven

in swabs that weretaken immediately after the phones were scrubbed.That suggests that washingwon't remove

all traces ofevidence from a criminal's device.So cell phones can now be added to the.__________(65)ofclues

that can clinch acrime-scene investigation._________(62)

A.upon

B.back

C.without

D.with