淘金高阶英语六级巅峰阅读 篇章阅读19：生物知识
<p> 篇章阅读19：生物知识</p><p> <span word="If">If</span> <span word="you">you</span> <span word="go">go</span> <span word="down">down</span> <span word="to">to</span> <span word="the">the</span> <span word="woods">woods</span> <span word="today">today</span>, <span word="you">you</span> <span word="may">may</span> <span word="meet">meet</span> <span word="high">high</span>-<span word="tech">tech</span> <span word="trees">trees</span> <span word="genetically">genetically</span> <span word="modified">modified</span> <span word="to">to</span> <span word="speed">speed</span> <span word="their">their</span> <span word="growth">growth</span> <span word="or">or</span> <span word="improve">improve</span> <span word="the">the</span> <span word="quality">quality</span> <span word="of">of</span> <span word="their">their</span> <span word="wood">wood</span>. <span word="Genetically">Genetically</span>-<span word="engineered">engineered</span> <span word="food">food</span> <span word="crops">crops</span> <span word="have">have</span> <span word="become">become</span> <span word="increasingly">increasingly</span> <span word="common">common</span>, <span word="albeit">albeit</span> <span word="controversial">controversial</span>. <span word="over">over</span> <span word="the">the</span> <span word="past">past</span> <span word="ten">ten</span> <span word="years">years</span>. <span word="But">But</span> <span word="genetic">genetic</span> <span word="engineering">engineering</span> <span word="of">of</span> <span word="trees">trees</span> <span word="has">has</span> <span word="lagged">lagged</span> <span word="behind">behind</span>.</p><p> <span word="Part">Part</span> <span word="of">of</span> <span word="the">the</span> <span word="reason">reason</span> <span word="is">is</span> <span word="technical">technical</span>. <span word="Understanding">Understanding</span>. <span word="and">and</span> <span word="then">then</span> <span word="altering">altering</span>, <span word="the">the</span> <span word="genes">genes</span> <span word="of">of</span> <span word="a">a</span> <span word="big">big</span> <span word="pine">pine</span> <span word="tree">tree</span> <span word="are">are</span> <span word="more">more</span> <span word="complex">complex</span> <span word="than">than</span> <span word="creating">creating</span> <span word="a">a</span> <span word="better">better</span> <span word="tomato">tomato</span>. <span word="While">While</span> <span word="tomatoes">tomatoes</span> <span word="sprout">sprout</span> <span word="happily">happily</span>, <span word="and">and</span> <span word="rapidly">rapidly</span>, <span word="in">in</span> <span word="the">the</span> <span word="laboratory">laboratory</span>, <span word="growing">growing</span> <span word="a">a</span> <span word="whole">whole</span> <span word="tree">tree</span> <span word="from">from</span> <span word="a">a</span> <span word="single">single</span>, <span word="genetically">genetically</span> <span word="altered">altered</span> <span word="cell">cell</span> <span word="in">in</span> <span word="a">a</span> <span word="test">test</span> <span word="tube">tube</span> <span word="is">is</span> <span word="a">a</span> <span word="tricky">tricky</span> <span word="process">process</span> <span word="that">that</span> <span word="takes">takes</span> <span word="years">years</span>, <span word="not">not</span> <span word="months">months</span>. <span word="Moreover">Moreover</span>. <span word="little">little</span> <span word="is">is</span> <span word="known">known</span> <span word="about">about</span> <span word="tree">tree</span> <span word="genes">genes</span>. <span word="Some">Some</span> <span word="trees">trees</span>, <span word="such">such</span> <span word="as">as</span> <span word="pine">pine</span> <span word="trees">trees</span>. <span word="have">have</span> <span word="a">a</span> <span word="lot">lot</span> <span word="of">of</span> <span word="DNA">DNA</span>-<span word="roughly">roughly</span> <span word="ten">ten</span> <span word="times">times</span> <span word="as">as</span> <span word="much">much</span> <span word="as">as</span> <span word="human">human</span>. <span word="And">And</span>, <span word="whereas">whereas</span> <span word="the">the</span> <span word="Human">Human</span> <span word="Genome">Genome</span> <span word="Project">Project</span> <span word="is">is</span> <span word="more">more</span> <span word="than">than</span> <span word="half">half</span>-<span word="way">way</span> <span word="through">through</span> <span word="its">its</span> <span word="task">task</span> <span word="of">of</span> <span word="isolating">isolating</span> <span word="and">and</span> <span word="sequencing">sequencing</span> <span word="the">the</span> <span word="estimated">estimated</span> 100,00 <span word="genes">genes</span> <span word="in">in</span> <span word="human">human</span> <span word="cells">cells</span>. <span word="similar">similar</span> <span word="efforts">efforts</span> <span word="to">to</span> <span word="analyze">analyze</span> <span word="tree">tree</span> <span word="genes">genes</span> <span word="are">are</span> <span word="still">still</span> <span word="just">just</span> <span word="saplings">saplings</span> .</p><p> <span word="Given">Given</span> <span word="the">the</span> <span word="large">large</span> <span word="number">number</span> <span word="of">of</span> <span word="tree">tree</span> <span word="genes">genes</span> <span word="and">and</span> <span word="the">the</span> <span word="little">little</span> <span word="that">that</span> <span word="is">is</span> <span word="known">known</span> <span word="about">about</span> <span word="them">them</span>, <span word="tree">tree</span> <span word="engineers">engineers</span> <span word="are">are</span> <span word="starting">starting</span> <span word="with">with</span> <span word="a">a</span> <span word="search">search</span> <span word="for">for</span> <span word="genetic">genetic</span> <span word="markers">markers</span> . <span word="The">The</span> <span word="first">first</span> <span word="step">step</span> <span word="is">is</span> <span word="to">to</span> <span word="isolate">isolate</span> <span word="DNA">DNA</span> <span word="from">from</span> <span word="trees">trees</span> <span word="with">with</span> <span word="desirable">desirable</span> <span word="properties">properties</span> <span word="such">such</span> <span word="as">as</span> <span word="insect">insect</span> <span word="resistance">resistance</span>. <span word="The">The</span> <span word="next">next</span> <span word="step">step</span> <span word="is">is</span> <span word="to">to</span> <span word="find">find</span> <span word="stretches">stretches</span> <span word="of">of</span> <span word="DNA">DNA</span> <span word="that">that</span> <span word="show">show</span> <span word="the">the</span> <span word="presence">presence</span> <span word="of">of</span> <span word="a">a</span> <span word="particular">particular</span> <span word="gene">gene</span>. <span word="Then">Then</span>, <span word="when">when</span> <span word="you">you</span> <span word="mate">mate</span> <span word="two">two</span> <span word="trees">trees</span> <span word="with">with</span> <span word="different">different</span> <span word="desirable">desirable</span> <span word="properties">properties</span>, <span word="it">it</span> <span word="is">is</span> <span word="simple">simple</span> <span word="to">to</span> <span word="check">check</span> <span word="which">which</span> <span word="offspring">offspring</span> <span word="contain">contain</span> <span word="them">them</span> <span word="all">all</span> <span word="by">by</span> <span word="looking">looking</span> <span word="for">for</span> <span word="the">the</span> <span word="genetic">genetic</span> <span word="markers">markers</span>. <span word="Henry">Henry</span> <span word="Amerson">Amerson</span>, <span word="at">at</span> <span word="North">North</span> <span word="Carolina">Carolina</span> <span word="State">State</span> <span word="University">University</span>, <span word="is">is</span> <span word="using">using</span> <span word="genetic">genetic</span> <span word="markers">markers</span> <span word="to">to</span> <span word="breed">breed</span> <span word="fungal">fungal</span> <span word="resistance">resistance</span> <span word="into">into</span> <span word="southern">southern</span> <span word="pines">pines</span>. <span word="Billions">Billions</span> <span word="of">of</span> <span word="these">these</span> <span word="are">are</span> <span word="grown">grown</span> <span word="across">across</span> <span word="America">America</span> <span word="for">for</span> <span word="pulp">pulp</span> <span word="and">and</span> <span word="paper">paper</span>, <span word="and">and</span> <span word="outbreaks">outbreaks</span> <span word="of">of</span> <span word="disease">disease</span> <span word="are">are</span> <span word="expensive">expensive</span>. <span word="But">But</span> <span word="not">not</span> <span word="all">all</span> <span word="individual">individual</span> <span word="trees">trees</span> <span word="are">are</span> <span word="susceptible">susceptible</span>. <span word="Dr">Dr</span>. <span word="Amerson">Amerson</span> <span word="s">s</span> <span word="group">group</span> <span word="has">has</span> <span word="found">found</span> <span word="markers">markers</span> <span word="that">that</span> <span word="distinguish">distinguish</span> <span word="fungus">fungus</span>-<span word="resistant">resistant</span> <span word="stock">stock</span> <span word="from">from</span> <span word="disease">disease</span>-<span word="prone">prone</span> <span word="trees">trees</span>.<span word="Using">Using</span> <span word="traditional">traditional</span> <span word="breeding">breeding</span> <span word="techniques">techniques</span>, <span word="they">they</span> <span word="are">are</span> <span word="introducing">introducing</span> <span word="the">the</span> <span word="resistance">resistance</span> <span word="genes">genes</span> <span word="into">into</span> <span word="pines">pines</span> <span word="on">on</span> <span word="test">test</span> <span word="sites">sites</span> <span word="in">in</span> <span word="America">America</span>.</p>
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