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  • DNA fingerprinting | Britannica.com
    The assay developed by Jeffreys has been supplanted by approaches that are based on the use of the polymerase chain reaction PCR and so called microsatellites or short tandem repeats STRs which have shorter repeat units typically 2 to 4 base pairs in length than minisatellites 10 to more than 100 base pairs in length PCR amplifies the desired fragment of DNA e g a specific STR many times over creating thousands of copies of the fragment It is an automated procedure that requires only small amounts of DNA as starting material and works even with partially degraded DNA Once an adequate amount of DNA has been produced with PCR the exact sequence of nucleotide pairs in a segment of DNA can be determined by using one of several biomolecular sequencing methods Automated equipment has greatly increased the speed of DNA sequencing and has made available many new practical applications including pinpointing segments of genes that cause genetic diseases mapping the human genome engineering drought resistant plants and producing biological drugs from genetically altered bacteria DNA fingerprinting scientist analyzing a DNA fingerprint image Terry Smith Time Life Pictures Getty Images An early use of DNA fingerprinting was in legal disputes notably to help solve crimes and to determine paternity The technique was challenged however over concerns about sample contamination faulty preparation procedures and erroneous interpretation of the results In addition RFLP required large amounts of high quality DNA which limited its application in forensics Forensic DNA samples frequently are degraded or are collected postmortem which means that they are lower quality and subject to producing less reliable results than samples that are obtained from a living individual Some of the concerns with DNA fingerprinting and specifically the use of RFLP subsided with the development of PCR and STR based approaches Comments Share Email Print Cite Last Updated 12 12 2014 You may also be interested in polymerase chain reaction complementation test genetics toxicological examination science anatomy toxicology test eugenics ecology chemotherapy quinine epigenetics Keep exploring Biology Bonanza Chemistry and Biology Fact or Fiction Human Health Fact or Fiction 7 Animals That Turn White in Winter 10 Inventions That Changed Your World What made you want to look up DNA fingerprinting To From Subject Comments Please limit to 900 characters Cancel Britannica Stories Behind The News Philosophy Religion Healing the Schism Pope Meets Patriarch Behind The News Science Gravitational Waves Observed Spotlight History Thomas Malthus s 250th Birthday See More Stories FEATURED QUIZZES Vocabulary Quiz True or False Spell It See More Quizzes About Us About Our Ads Contact Us Privacy Policy Terms of Use 2016 Encyclopædia Britannica Inc MLA style DNA fingerprinting Encyclopædia Britannica Encyclopædia Britannica Online Encyclopædia Britannica Inc 2016 Web 12 Feb 2016 http www britannica com science DNA fingerprinting APA style DNA fingerprinting 2016 In Encyclopædia Britannica Retrieved from http www britannica com science DNA fingerprinting Harvard style DNA fingerprinting 2016 Encyclopædia Britannica Online Retrieved 12 February 2016 from http www britannica com science DNA fingerprinting Chicago

    Original URL path: http://www.britannica.com/science/DNA-fingerprinting (2016-02-13)
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  • Biology Bonanza Quiz | Britannica.com
    score When you re done try again to beat your best score vm state secondsLeft fixedLength 2 QUESTION vm state currentQuestion 1 of vm questions length Timer Score vm state score Biology Bonanza vm state secondsLeft fixedLength 2 QUESTION vm state currentQuestion 1 of vm questions length Timer Score vm state score Biology Bonanza 0 vm state nextLabel Quiz Results Biology Bonanza vm state numberCorrect vm questions length correct vm state score vm maxPoints points Replay Share your score Log in to save your score Science Fire in the Sky Fact or Fiction Pop Culture Cary Grant Quiz Sports Recreation American Sports Nicknames Music Phenomenon From Across the Pond Arts Culture Clowning Around Are you a Quizmaster Log in to save your score and compete against the community Compare your score Max Score vm maxPoints New Best Score vm state score vm communityAverage number 0 Your Score Community Average High scores Your results vm state responsesVisible Hide Show Answers Questions Correct vm state numberCorrect vm questions length Total Score vm state score vm maxPoints Question Question index 1 Your Answer No response vm state responses index isCorrect Your Correct Answer Back to Top Literature Language Parlez Vous Français And Other

    Original URL path: http://www.britannica.com/quiz/biology-bonanza (2016-02-13)
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  • Chemistry and Biology: Fact or Fiction Quiz | Britannica.com
    try again to beat your best score vm state secondsLeft fixedLength 2 QUESTION vm state currentQuestion 1 of vm questions length Timer Score vm state score Chemistry and Biology Fact or Fiction vm state secondsLeft fixedLength 2 QUESTION vm state currentQuestion 1 of vm questions length Timer Score vm state score Chemistry and Biology Fact or Fiction 0 vm state nextLabel Quiz Results Chemistry and Biology Fact or Fiction vm state numberCorrect vm questions length correct vm state score vm maxPoints points Replay Share your score Log in to save your score Science Science Quiz Sports Recreation Sports Fact or Fiction Literature Language The Literary World History Infamous Nazis Arts Culture Artists Painters Fact or Fiction Are you a Quizmaster Log in to save your score and compete against the community Compare your score Max Score vm maxPoints New Best Score vm state score vm communityAverage number 0 Your Score Community Average High scores Your results vm state responsesVisible Hide Show Answers Questions Correct vm state numberCorrect vm questions length Total Score vm state score vm maxPoints Question Question index 1 Your Answer No response vm state responses index isCorrect Your Correct Answer Back to Top Pop Culture A List

    Original URL path: http://www.britannica.com/quiz/chemistry-and-biology-fact-or-fiction (2016-02-13)
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  • Nature: Tip of the Iceberg Quiz | Britannica.com
    try again to beat your best score vm state secondsLeft fixedLength 2 QUESTION vm state currentQuestion 1 of vm questions length Timer Score vm state score Nature Tip of the Iceberg Quiz vm state secondsLeft fixedLength 2 QUESTION vm state currentQuestion 1 of vm questions length Timer Score vm state score Nature Tip of the Iceberg Quiz 0 vm state nextLabel Quiz Results Nature Tip of the Iceberg Quiz vm state numberCorrect vm questions length correct vm state score vm maxPoints points Replay Share your score Log in to save your score Geography Australia Fact or Fiction Society Christmas Sports Recreation Ready Set Know Literature Language Famous Poets and Poetic Form Music Rock Music and Rock n Roll Are you a Quizmaster Log in to save your score and compete against the community Compare your score Max Score vm maxPoints New Best Score vm state score vm communityAverage number 0 Your Score Community Average High scores Your results vm state responsesVisible Hide Show Answers Questions Correct vm state numberCorrect vm questions length Total Score vm state score vm maxPoints Question Question index 1 Your Answer No response vm state responses index isCorrect Your Correct Answer Back to Top History Robert

    Original URL path: http://www.britannica.com/quiz/nature-tip-of-the-iceberg-quiz (2016-02-13)
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  • Editor Picks: Our Favorite Dinosaurs | Britannica.com
    dinosaur had been the T rex T rex was immense but the velociraptors clearly stole the movie Imagine my surprise when I learned that in actuality although they reached up to 1 8 meters 6 feet in length velociraptors weren t much larger than a turkey standing just under 0 6 meter 2 feet in height However their trademark large sickle shaped claws on their second toes and swift agile hunting still made them formidable predators Even with their smaller size I suspect that humans would still have had a difficult time fending off hungry velociraptors And anyway one of my favorite bands the Doubleclicks created a song about how cool velociraptors are Sorry T rex 3 Erik Ankylosaurus Encyclopædia Britannica Inc Since childhood my favorite dinosaur has been Ankylosaurus a creature so overdesigned that it seems too good to be true With spikes on its head and side a back covered with armored plates and a tail that ended in a massive club of bone it was more spectacularly protected from predators than Stegosaurus with its ostentatious plates Imagine a giant combination of a turtle and a rhinoceros Paradoxically this coolest of dinosaurs didn t appear in many movies until Jurassic World And you know why Every time you see a fight between a T rex and some hapless Triceratops it s all over once T rex gets behind the frill You can t get behind Ankylosaurus Get in its blind spot and you get its giant bony club in your face There is no fair fight with an ankylosaur Which I hear dies at the hand of the made up dino villain in Jurassic World To which I say 1 Boooo and 2 We all know that wouldn t happen 2 Richard Compsognathus Encyclop dia Britannica Inc I love the diminutive members of the genus Compsognathus for the remarkable sense of scale they provide They were about the size of a turkey exponentially smaller than their theropod relatives the tyrannosaurs but they possessed the same elegantly raptorial proportions darting about on their lithe back legs and snapping up smaller creatures They ate lizards as evidenced by a specimen found inside the ribcage of one fossil The size and whippetlike figure of Compsognathus strongly suggest the evolutionary continuum between birds and dinosaurs Indeed a fossil of a related species boasts preserved protofeathers suggesting that Compsognathus may have had them as well 1 John R Therizinosaurus Encyclop dia Britannica Inc The therizinosaurs are scary looking late Cretaceous theropods from Asia and North America They were probably not carnivorous despite their nightmarish Freddy Krueger claws These unusual dinosaurs had a small skull and leaf shaped teeth but lacked teeth in the front half of the upper jaw If I were lucky enough to direct a big budget dinosaur movie therizinosaurs would be the first ones the audience would see Your Reaction Editor Picks My Favorite Frogs of the Tropics Everything s Illuminated 6 Bioluminescent Organisms MORE Science LISTS Editor Picks Top

    Original URL path: http://www.britannica.com/list/editor-picks-our-favorite-dinosaurs (2016-02-13)
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  • My Favorite Frogs (of Canada and the United States) | Britannica.com
    A species commonly heard but rarely seen in North America is the spring peeper Pseudacris crucifer so named for its peep call which is prominent at the start of spring Spring peepers measure about an inch in length when full grown and often can be identified by a dark X or X like markings on the back They are exceedingly difficult to find given their small size and their tendency to live in the debris on the forest floor and at the grassy edges of swamps and ponds Their native range extends across the central and eastern regions of Canada and the United States Two subspecies are recognized the northern spring peeper P crucifer crucifer and the southern spring peeper P crucifer bartramiana 4 Pickerel Frog Aaron Sherman The pickerel frog Lithobates palustris is unique among spotted frogs in North America for the shape of the dark markings on its body which are more square or rectangular than round round markings are common on most other species of spotted frogs The markings are arranged on the back in two columns which at their outer edges are paralleled by white or yellow ridge lines that run the length of the back Dark bands on the legs add to the pickerel frog s natural camouflage Although sometimes confused with the leopard frog the pickerel frog has a distinguishing orange coloration to the underside of its gangly legs It is found across eastern Canada most of the eastern United States and parts of the Midwest 3 Mink Frog Encyclopædia Britannica Inc The odor given off in the skin secretions of the mink frog Lithobates septentrionalis has been likened to the stench of a rotten onion which happens to be similar to the odor of a mink The mink frog is found in the north central and northeastern regions of the United States and the central and eastern parts of Canada It spends much of its time in or near water particularly bodies of water that host large populations of water lilies The mink frog uses the plants floating leaves better known as lily pads as a means of escape from potential predators 2 Columbia Spotted Frog Another favorite is the Columbia spotted frog Rana luteiventris a species common in western North America where its range extends from southeastern Alaska to Nevada It is known particularly for the irregularly shaped spots on its back which typically are dark with light centers and for the bright reddish or bronze coloration on the underside of its plump belly and legs The Columbia spotted frog is a mostly aquatic species inhabiting wet areas close to ponds marshes and lakes It is an adept swimmer with extensive webbing found between the toes of its hind feet 1 Northern Pacific Tree Frog RONSAN4D iStock Thinkstock The northern Pacific tree frog Pseudacris regilla or simply Pacific tree frog has unusually long toes equipped with sticky pads that help it cling to the vegetation in its habitat which extends along coastal

    Original URL path: http://www.britannica.com/list/my-favorite-frogs-of-canada-and-the-united-states (2016-02-13)
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  • Thor Heyerdahl | Britannica.com
    of Pitcairn Island and 2 200 miles west of Chile Forming a triangle 14 miles long by seven miles wide it has an area of 63 square miles 163 square kilometres its highest point Mount Terevaka is 1 969 feet 600 metres above sea level To its original inhabitants the island is known as Rapa Nui Great Rapa or Te Pito te Henua Navel of the World The first European

    Original URL path: http://www.britannica.com/contributor/Thor-Heyerdahl/1317 (2016-02-13)
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  • Easter Island | Britannica.com
    Easter Island Ahu Nau Nau Ahu Nau Nau Easter Island Chile Easter Island Ahu Tongariki Ahu Tongariki Easter Island Chile Easter Island moai figures Moai or stone statue Easter Island Easter Island Rano Raraku Rano Raraku Easter Island Chile Easter Island sculptures cut from volcanic rock Sculptures cut from volcanic rock Easter Island You may also be interested in Media for Chile Media for New Zealand Media for Papua New

    Original URL path: http://www.britannica.com/place/Easter-Island/images-videos (2016-02-13)
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