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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>One gene makes one protein :: DNA from the Beginning</title> <meta name="description" content="Beadle and Tatum learn that mutations inactivate proteins." /> <link rel="preload" as="style" src="/css/main.css"> <link rel="preload" as="script" src="/js/swfobject.js"> <link rel="preload" as="script" src="/js/prototype-1.6.1.js"> <link href="/css/main.css" rel="stylesheet" type="text/css" /> <link href='https://fonts.googleapis.com/css?family=Droid+Serif' rel='stylesheet' type='text/css'/> <link href='https://fonts.googleapis.com/css?family=Droid+Sans' rel='stylesheet' type='text/css'/> <script type="text/javascript" src="/js/swfobject.js"></script> <script type="text/javascript" src="/js/prototype-1.6.1.js"></script> </head> <body> <div id="container"> <div id="content"> <div id="header"> <div class="rollover-home"> <a href="/" class="rollover-home" title="DNA from the Beginning Home"><span class="displace">Home</span></a> </div> </div>  <div id="content-container"> <h1><span> Concept 16</span> One gene makes one protein.</h1> <div id="nav"> <ul> <li class="menu1"><a href="index.html" title="CONCEPT" ><span class="displace">CONCEPT</span></a></li> <li class="menu2"><a href="animation.html" title="ANIMATION"><span class="displace">ANIMATION</span></a></li> <li class="menu3"><a href="gallery.html" title="GALLERY"><span class="displace">GALLERY</span></a></li> <li class="menu4"><a href="av.html" title="VIDEO"><span class="displace">VIDEO</span></a></li> <li class="menu5"><a href="bio.html" title="BIO"><span class="displace">BIO</span></a></li> <li class="menu6"><a href="problem.html" title="PROBLEM"><span class="displace">PROBLEM</span></a></li> <li class="menu7"><a href="links.html" title="LINKS" ><span class="displace">LINKS</span></a></li> </ul> <br class="clearfloat" /> </div> <div id="concept"> <img src="/images/16/concept16.jpg" class="concept-image" alt="One gene makes one protein." /> <p>In 1902, Archibald Garrod described the inherited disorder alkaptonuria as an "inborn error of metabolism." He proposed that a gene mutation causes a specific defect in the biochemical pathway for eliminating liquid wastes. The phenotype of the disease — dark urine — is a reflection of this error. </p> <p>This hypothesis was rigorously proven in 1941 by George Beadle and Edward Tatum, using the simple bread mold <em>Neurospora</em>. First, they found that molds exposed to radiation lose the ability to produce essential nutrients, and this slowed, even stopped the growth of the mold. Then, they found that growth can be restored by providing the mutated mold with a specific supplement. They reasoned that each mutation must inactivate the enzyme (protein) needed to synthesize the nutrient. Thus, one gene carries the directions for making one protein. </p> </div> </div> <br class="clearfloat" /> <div id="footer"> <ul> <li><a href="/">Home</a></li> <li><a href="/sitemap.html">Site Map</a></li> <li><a href="/scientists.html">Scientists</a></li> <li><a href="/glossary.html">Glossary</a></li> <li><a href="/feedback.html">Feedback</a></li> <li><a href="/awards.html">Awards</a></li> <li><a href="/credits.html">Credits</a></li> <li><a href="http://blogs.dnalc.org/dnaftb/" style="background-image:none;">Blog</a></li> </ul> <p> Funded by <a href="http://macyfoundation.org">The Josiah Macy, Jr. Foundation</a><br /> © 2002 - 2011, <a href="http://www.dnalc.org/"> DNA Learning Center</a>, <a href="https://www.cshl.edu/">Cold Spring Harbor Laboratory</a>. All rights reserved. </p> </div>  </div> <div id="sidebar"> <div id="search" > <form method="get" action="/search"> <div class="fieldHolder1"> <input type="search" id="q" name="q" placeholder="Search" onclick="this.value=''" value="" /> <img style="background-color:#9C0;" src="/images/general/search_icon.jpg" alt="Search" onclick="document.forms[0].submit()" /> </div> </form> </div>  <div id="sidebar"> <ul class="menu-side"> <li class="section1" style="margin-bottom: 3px;"><a href="/1/index.html" title="Classical Genetics"><span class="displace">CLASSICAL GENETICS</span></a></li> </ul> <ul class="sections-side sections-side2a" style="padding-top: 56px;"> <li ><a href="/15/"><img src="/images/thumbnails/15-thumb-sm.png" alt="15." />DNA and proteins are key molecules of the cell nucleus.</a></li> <li ><a class="concept-highlight" href="/16/"><img src="/images/thumbnails/16-thumb-sm.png" alt="16." />One gene makes one protein.</a></li> <li ><a href="/17/"><img src="/images/thumbnails/17-thumb-sm.png" alt="17." />A gene is made of DNA.</a></li> <li ><a href="/18/"><img src="/images/thumbnails/18-thumb-sm.png" alt="18." />Bacteria and viruses have DNA too.</a></li> <li ><a href="/19/"><img src="/images/thumbnails/19-thumb-sm.png" alt="19." />The DNA molecule is shaped like a twisted ladder.</a></li> <li ><a href="/20/"><img src="/images/thumbnails/20-thumb-sm.png" alt="20." />A half DNA ladder is a template for copying the whole.</a></li> <li ><a href="/21/"><img src="/images/thumbnails/21-thumb-sm.png" alt="21." />RNA is an intermediary between DNA and protein.</a></li> <li ><a href="/22/"><img src="/images/thumbnails/22-thumb-sm.png" alt="22." />DNA words are three letters long.</a></li> <li ><a href="/23/"><img src="/images/thumbnails/23-thumb-sm.png" alt="23." />A gene is a discrete sequence of DNA nucleotides.</a></li> <li ><a href="/24/"><img src="/images/thumbnails/24-thumb-sm.png" alt="24." />The RNA message is sometimes edited.</a></li> <li ><a href="/25/"><img src="/images/thumbnails/25-thumb-sm.png" alt="25." />Some viruses store genetic information in RNA.</a></li> <li ><a href="/26/"><img src="/images/thumbnails/26-thumb-sm.png" alt="26." />RNA was the first genetic molecule.</a></li> <li ><a href="/27/"><img src="/images/thumbnails/27-thumb-sm.png" alt="27." />Mutations are changes in genetic information.</a></li> <li style="border-bottom: 1px solid #669;"><a href="/28/"><img src="/images/thumbnails/28-thumb-sm.png" alt="28." />Some types of mutations are automatically repaired.</a></li> </ul> <ul class="menu-side"> <li class="section3"><a href="/29/index.html" title="Genetic Organization and Control"><span class="displace">GENETIC ORGANIZATION AND CONTROL</span></a></li> </ul> </div> </div>  <br class="clearfloat" /> </div>  <script type="text/javascript"> Event.observe(window, 'load', function() { var uri = '/16/index.html'; uri = uri.replace(/-\d/,''); $('nav').down().descendants().each(function(s) { if (s.nodeName == 'A') { if (s.href.match(uri)) { s.addClassName('current'); throw $break; } } }); }); </script> <script type="text/javascript"> var _gaq = _gaq || []; _gaq.push(['_setAccount', 'UA-1818773-10']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = 'https://www.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); </script>  <script async src="https://www.googletagmanager.com/gtag/js?id=G-K6EHFCRJBP"></script> <script> window.dataLayer = window.dataLayer || []; function gtag(){dataLayer.push(arguments);} gtag('js', new Date()); gtag('config', 'G-K6EHFCRJBP'); </script> </body> </html>