Introduction to genetic engineering | Molecular genetics | High school biology | Khan Academy — Transcript

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1. 0:00the idea of genetic engineering is
2. 0:04something that we associate with with
3. 0:05the 20th century we didn't even know
4. 0:08that genes were actually the mechanism
5. 0:11of heredity until the middle of the 20th
6. 0:14century and the direct modification of
7. 0:17genes for some purpose really didn't
8. 0:19even start happening until the 1970s but
9. 0:23it's worth noting that human beings have
10. 0:25been in some ways influencing the
11. 0:28genetics of organisms for a very very
12. 0:31very long time
13. 0:33for example in nature you have things
14. 0:36that look like this we call them wolves
15. 0:39but today in our lives we also have
16. 0:42things that look like this now these
17. 0:45dogs did not come about naturally they
18. 0:47came about from many generations of
19. 0:51breeding of human beings taking things
20. 0:54that started off looking like wolves or
21. 0:56foxes and selecting for certain traits
22. 0:59they might have selected for traits that
23. 1:01maybe they're small and they look more
24. 1:03like puppies even where they're full
25. 1:04grown or traits that they are more
26. 1:06docile they're more likely to listen to
27. 1:08what a human being says to do or traits
28. 1:11that they're good at killing rodents or
29. 1:13whatever else it might be and over time
30. 1:15repeated selection of those traits led
31. 1:18to what we see as these different breeds
32. 1:21of dogs so even though human beings were
33. 1:23doing this for hundreds and thousands of
34. 1:26years they were influencing what dna
35. 1:29gets passed on from one generation to
36. 1:31another they didn't know about the
37. 1:33actual genetic code but it was a form of
38. 1:36genetic manipulation nonetheless
39. 1:39similarly if you look into the plant
40. 1:42kingdom when you go to the store and you
41. 1:44see that sweet apple things like that
42. 1:47might not have existed in the form that
43. 1:49you see them today it is very likely in
44. 1:51fact most agricultural products people
45. 1:54might have found wild apples and we
46. 1:56could be talking thousands of years ago
47. 1:58they might have found wild apple trees
48. 2:01let me draw a quick
49. 2:02apple tree here
50. 2:04and they might have found that the
51. 2:05apples were a little bit sour and small
52. 2:08and hard to eat and hard to digest but
53. 2:11over time people selected the trees that
54. 2:14had sweeter apples that had larger
55. 2:16apples and made the conditions so that
56. 2:18they were more likely to reproduce so
57. 2:20over time you got larger and sweeter
58. 2:22apples like the type that you see at
59. 2:24your store and as i mentioned most
60. 2:26agricultural products that we have today
61. 2:28are the result of hundreds or thousands
62. 2:31of years of this type of breeding so
63. 2:34even though that might not be the formal
64. 2:36definition of genetic engineering which
65. 2:38typically is referring to something like
66. 2:40gene modification which we've only been
67. 2:42able to do in the last few decades human
68. 2:44beings have been doing some type of
69. 2:46influence on organisms dna for a very
70. 2:48very long time
71. 2:50but with that said in the last few
72. 2:53decades we've we've been able to become
73. 2:55much much more precise with influencing
74. 2:58dna through genetic engineering in other
75. 3:02videos we'll go more detail about how
76. 3:04that is done but you have this idea of
77. 3:07recombinant dna
78. 3:09combinant
79. 3:11dna where you could take genes from one
80. 3:14organism and put them in another
81. 3:15organism and you might say why is this
82. 3:18useful
83. 3:19well let's say that there is a tree you
84. 3:21want to grow let's say it's an apple
85. 3:22tree but it's very susceptible to a
86. 3:24certain type of disease and if that
87. 3:26disease hits you lose all of your crop
88. 3:28but what if you could insert into the
89. 3:30dna of that apple tree
90. 3:32maybe
91. 3:33a gene that makes it more resistant to
92. 3:36that disease and this is what people
93. 3:39actually do today so they will insert
94. 3:42insert
95. 3:44dna and it could be some from pretty
96. 3:46wild things i've read stories about
97. 3:48insert inserting insect dna into a plant
98. 3:51so that it will be more robust in some
99. 3:52way or another
100. 3:54now this idea of recombinant dna
101. 3:58and genetically modifying food this is
102. 4:00often known as a genetically modified
103. 4:03organism this is somewhat controversial
104. 4:06many people say hey this is good it
105. 4:08allows us to produce more robust foods
106. 4:11in fact part of this recombinant dna
107. 4:13inserting dna into something else it
108. 4:16might make it more nutritious it might
109. 4:18provide for more vitamins but other
110. 4:20people would argue that hey we don't
111. 4:21know exactly what all the repercussions
112. 4:24of what we're doing will happen we might
113. 4:26think it's helpful but when you're
114. 4:28taking what dna from one organism and
115. 4:30putting it into another how does that
116. 4:32affect the nutrition or the long-lasting
117. 4:34effects of eating that over time so this
118. 4:36is something for you to think about and
119. 4:38we're starting to go when we start
120. 4:40asking these questions into the field of
121. 4:43bioethics as we have more and more
122. 4:45control over the genome and especially
123. 4:48as we'll see the human genome there's
124. 4:50questions that we have to ask about is
125. 4:52it good or is it bad
126. 4:54but going back to this idea of genetic
127. 4:56engineering and recombinant dna other
128. 4:59things that you could do is you could t
129. 5:01let's say that we need to produce
130. 5:03insulin for diabetics well maybe you can
131. 5:06take a bacteria cell and insert into the
132. 5:10bacteria cell the gene that helps
133. 5:13produce for insulin and then all of a
134. 5:14sudden that bacteria cell can become a
135. 5:17human insulin producing factory so that
136. 5:20we can have more insulin for diabetics
137. 5:22that this insulin could then be
138. 5:23harvested that is a use of recombinant
139. 5:26dna
140. 5:27and so we really are going into an
141. 5:29interesting period in humanity for many
142. 5:32thousands of years we were breeding
143. 5:34things but now we're learning to
144. 5:36manipulate things at a very fine grain
145. 5:39level and it makes us ask all sorts of
146. 5:42questions there are likely to be some
147. 5:44very good things we can do produce new
148. 5:46medicines produce more robust crops but
149. 5:49there are also questions about what are
150. 5:51the side effects and the bio ethics get
151. 5:54really interesting when we start
152. 5:55thinking about modifying the human
153. 5:57genome itself because when you're
154. 5:59modifying genetics you're not just
155. 6:00modifying one organism you're modifying
156. 6:02all of their offspring you're modifying
157. 6:04the genes that exist in the gene pool
158. 6:07and so some very good arguments for
159. 6:08modifying the human genome are
160. 6:10correcting diseases some things that
161. 6:12could be very serious but over time
162. 6:14things might people might say hey i want
163. 6:16to be a little bit taller or i want a
164. 6:17certain hair color i want straighter
165. 6:19teeth or they might say i want a child
166. 6:21who has this trait or that trait so
167. 6:23things get very very interesting the
168. 6:25more we think about how genetic
169. 6:28engineering may be used