Editing Recombinant DNA (section)

==Applications of recombinant DNA==

Recombinant DNA is widely used in [[biotechnology]], medicine and research. Today, recombinant proteins and other products that result from the use of DNA technology are found in essentially every pharmacy, physician or veterinarian office, medical testing laboratory, and biological research laboratory. In addition, organisms that have been manipulated using recombinant DNA technology, as well as products derived from those organisms, have found their way into many farms, [[Genetically modified food|supermarkets]], [[Humulin|home medicine cabinets]], and even pet shops, such as those that sell [[GloFish]] and other [[genetically modified animal]]s.

The most common application of recombinant DNA is in basic research, in which the technology is important to most current work in the biological and biomedical sciences.<ref name="isbn1-4051-1121-6" /> Recombinant DNA is used to identify, map and sequence genes, and to determine their function. rDNA probes are employed in analyzing gene expression within individual cells, and throughout the tissues of whole organisms. Recombinant proteins are widely used as reagents in laboratory experiments and to generate antibody probes for examining protein synthesis within cells and organisms.<ref name="isbn0-8153-4111-3" />

Many additional practical applications of recombinant DNA are found in industry, food production, human and veterinary medicine, agriculture, and bioengineering.<ref name="isbn0-8153-4111-3" /> Some specific examples are identified below.

===Recombinant chymosin===
Found in [[rennet]], [[chymosin]] is the enzyme responsible for hydrolysis of ''κ''-[[casein]] to produce para-''κ''-casein and [[glycomacropeptide]], which is the first step in formation of [[cheese]], and subsequently [[curd]], and [[whey]].<ref>{{cite book |doi=10.1533/9780857093639.13 |chapter=Caseins |title=Handbook of Food Proteins |date=2011 |last1=O'Kennedy |first1=B.T. |pages=13–29 |isbn=978-1-84569-758-7 }}</ref> It was the first genetically engineered food additive used commercially. Traditionally, processors obtained chymosin from rennet, a preparation derived from the fourth stomach of milk-fed calves. Scientists engineered a non-pathogenic strain (K-12) of ''[[E. coli]]'' bacteria for large-scale laboratory production of the enzyme. This microbiologically produced recombinant enzyme, identical structurally to the calf derived enzyme, costs less and is produced in abundant quantities. Today about 60% of U.S. hard cheese is made with genetically engineered chymosin. In 1990, FDA granted chymosin "[[generally recognized as safe]]" (GRAS) status based on data showing that the enzyme was safe.<ref>Donna U. Vogt and Mickey Parish. (1999) [https://fpc.state.gov/6176.htm Food Biotechnology in the United States: Science, Regulation, and Issues]</ref>

===Recombinant human insulin===
Recombinant human [[insulin]] has almost completely replaced insulin obtained from animal sources (e.g. pigs and cattle) for the treatment of [[type 1 diabetes]]. A variety of different recombinant insulin preparations are in widespread use.<ref name="pmid|12004916">{{Cite journal
| last1 = Gualandi-Signorini | first1 = A.
| last2 = Giorgi | first2 = G.
| title = Insulin formulations--a review
| journal = European Review for Medical and Pharmacological Sciences
| volume = 5
| issue = 3
| pages = 73–83
| year = 2001
| pmid = 12004916
| url = https://www.europeanreview.org/wp/wp-content/uploads/176.pdf
}}</ref> Recombinant insulin is synthesized by inserting the human insulin gene into ''[[E. coli]]'', or yeast (Saccharomyces cerevisiae)<ref>[[Insulin aspart|#Insulin aspart]]</ref> which then produces insulin for human use.<ref>{{Cite web |title=Insulin human |url=https://go.drugbank.com/drugs/DB00030 |access-date=2023-12-10 |website=go.drugbank.com}}</ref> Insulin produced by E. coli requires further [[post translational modification]]s (e.g. glycosylation) whereas yeasts are able to perform these modifications themselves by virtue of being more complex host organisms. The advantage of recombinant human insulin is after chronic use patients don't develop an immune defence against it the way animal sourced insulin stimulates the human immune system.<ref>{{Cite web |last=Mills |first=Joshua |date=2022-05-16 |title=HSC Biology Recombinant technology: Insulin production |url=https://edzion.com/2022/05/16/hsc-biology-recombinant-technology-insulin-production/ |access-date=2022-12-26 |website=Edzion |language=en-US}}</ref>
===Recombinant human [[growth hormone]] (HGH, somatotropin)===
Administered to patients whose pituitary glands generate insufficient quantities to support normal growth and development. Before recombinant HGH became available, HGH for therapeutic use was obtained from pituitary glands of cadavers. This unsafe practice led to some patients developing [[Creutzfeldt–Jakob disease]]. Recombinant HGH eliminated this problem, and is now used therapeutically.<ref name="pmid|18786336">{{Cite journal
 | last1 = Von Fange | first1 = T.
 | last2 = McDiarmid | first2 = T.
 | last3 = MacKler | first3 = L.
 | last4 = Zolotor | first4 = A.
 | title = Clinical inquiries: Can recombinant growth hormone effectively treat idiopathic short stature?
 | journal = The Journal of Family Practice
 | volume = 57
 | issue = 9
 | pages = 611–612
 | year = 2008
 | pmid = 18786336
 | id = {{Gale|A185211006}}
 | url = https://cdn.mdedge.com/files/s3fs-public/Document/September-2017/5709JFP_Clinicalinq3.pdf
}}</ref> It has also been misused as a performance-enhancing drug by athletes and others.<ref name="pmid|19141266">{{Cite journal
 | last1 = Fernandez | first1 = M.
 | last2 = Hosey | first2 = R.
 | title = Performance-enhancing drugs snare nonathletes, too
 | journal = The Journal of Family Practice
 | volume = 58
 | issue = 1
 | pages = 16–23
 | year = 2009
 | pmid = 19141266
 | id = {{Gale|A197493722}}
 | url = https://cdn.mdedge.com/files/s3fs-public/Document/September-2017/5801JFP_Article2.pdf
}}</ref><ref>{{Cite web |title=Somatotropin |url=https://go.drugbank.com/drugs/DB00052 |access-date=2023-12-10 |website=go.drugbank.com |language=en}}</ref>

===Recombinant blood clotting factor VIII===
It is the recombinant form of [[factor VIII]], a blood-clotting protein that is administered to patients with the bleeding disorder [[hemophilia]], who are unable to produce factor VIII in quantities sufficient to support normal blood coagulation.<ref name="pmid|21056743">{{Cite journal
 | last1 = Manco-Johnson | first1 = M. J.
 | doi = 10.1016/j.yapd.2010.08.007
 | title = Advances in the Care and Treatment of Children with Hemophilia
 | journal = Advances in Pediatrics
 | volume = 57
 | issue = 1
 | pages = 287–294
 | year = 2010
 | pmid = 21056743
}}</ref> Before the development of recombinant factor VIII, the protein was obtained by processing large quantities of human blood from multiple donors, which carried a very high risk of transmission of [[Blood-borne disease|blood borne infectious diseases]], for example HIV and hepatitis B.

===Recombinant hepatitis B vaccine===
[[Hepatitis B]] infection can be successfully controlled through the use of a recombinant [[subunit vaccine|subunit]] [[hepatitis B vaccine]], which contains a form of the hepatitis B virus surface antigen that is produced in yeast cells. The development of the recombinant subunit vaccine was an important and necessary development because hepatitis B virus, unlike other common viruses such as [[polio virus]], cannot be grown [[in vitro]].<ref>{{Cite web |date=2011-06-28 |title=Hepatitis B Vaccine Information from Hepatitis B Foundation |url=http://www.hepb.org/hepb/vaccine_information.htm |access-date=2023-12-10 |archive-url=https://web.archive.org/web/20110628230253/http://www.hepb.org/hepb/vaccine_information.htm |archive-date=2011-06-28 }}</ref>

===Recombinant antibodies===
[[Recombinant antibodies]] (rAbs) are produced in vitro by the means of expression systems based on mammalian cells. Their monospecific binding to a specific epitope makes rAbs eligible not only for research purposes, but also as therapy options against certain cancer types, infections and autoimmune diseases.<ref>{{Cite news |last=Narang |first=Aarti |date=2022 |title=Recombinant Antibodies: Next level in antibody technology |newspaper=Evitria - |url=https://www.evitria.com/journal/recombinant-antibodies/recombinant-antibodies-next-level-antibody-technology/ }}</ref>

===Diagnosis of HIV infection===
Each of the three widely used methods for [[HIV test|diagnosing HIV infection]] has been developed using recombinant DNA. The antibody test ([[ELISA]] or [[western blot]]) uses a recombinant HIV protein to test for the presence of [[antibodies]] that the body has produced in response to an HIV infection. The DNA test looks for the presence of HIV genetic material using [[reverse transcription polymerase chain reaction]] (RT-PCR). Development of the RT-PCR test was made possible by the molecular cloning and sequence analysis of HIV genomes. [https://www.cdc.gov/hiv/topics/testing/index.htm HIV testing page from US Centers for Disease Control (CDC)]

===Golden rice===
[[Golden rice]] is a recombinant variety of rice that has been engineered to express the enzymes responsible for [[β-carotene]] biosynthesis.<ref name="pmid|10634784" /> This variety of rice holds substantial promise for reducing the incidence of [[vitamin A deficiency]] in the world's population.<ref name="pmid|15793573">{{Cite journal
 | last1 = Paine | first1 = J. A.
 | last2 = Shipton | first2 = C. A.
 | last3 = Chaggar | first3 = S.
 | last4 = Howells | first4 = R. M.
 | last5 = Kennedy | first5 = M. J.
 | last6 = Vernon | first6 = G.
 | last7 = Wright | first7 = S. Y.
 | last8 = Hinchliffe | first8 = E.
 | last9 = Adams | first9 = J. L.
 | last10 = Silverstone
 | doi = 10.1038/nbt1082 | first10 = A. L.
 | last11 = Drake | first11 = R.
 | title = Improving the nutritional value of Golden Rice through increased pro-vitamin a content
 | journal = Nature Biotechnology
 | volume = 23
 | issue = 4
 | pages = 482–487
 | year = 2005
 | pmid = 15793573
 }}</ref> Golden rice is not currently in use, pending the resolution of regulatory and intellectual property issues.<ref>{{Cite web |last=DHNS |title=Foreign group roots for 'golden rice' in India |url=https://www.deccanherald.com/india/foreign-group-roots-golden-rice-2118105 |access-date=2023-12-10 |website=Deccan Herald |language=en}}</ref>

===Herbicide-resistant crops===
Commercial varieties of important agricultural crops (including soy, maize/corn, sorghum, canola, alfalfa and cotton) have been developed that incorporate a recombinant gene that results in resistance to the herbicide [[glyphosate]] (trade name ''Roundup''), and simplifies weed control by glyphosate application.<ref name="pmid|16916934">{{Cite journal
| last1 = Funke | first1 = T.
| last2 = Han | first2 = H.
| last3 = Healy-Fried | first3 = M.
| last4 = Fischer | first4 = M.
| last5 = Schönbrunn | first5 = E.
| title = Molecular basis for the herbicide resistance of Roundup Ready crops
| doi = 10.1073/pnas.0603638103
| journal = Proceedings of the National Academy of Sciences
| volume = 103
| issue = 35
| pages = 13010–13015
| year = 2006
| pmid = 16916934
| pmc =1559744
| bibcode = 2006PNAS..10313010F
| doi-access = free
}}</ref> These crops are in common commercial use in several countries.

===Insect-resistant crops===
''[[Bacillus thuringiensis]]'' is a bacterium that naturally produces a protein ([[Bt toxin]]) with insecticidal properties.<ref name="pmid|15793573" /> The bacterium has been applied to crops as an insect-control strategy for many years, and this practice has been widely adopted in agriculture and gardening. Recently, plants have been developed that express a recombinant form of the bacterial protein, which may effectively control some insect predators. Environmental issues associated with the use of these [[transgenic]] crops have not been fully resolved.<ref name="pmid|12949561">{{Cite journal
 | last1 = Mendelsohn | first1 = M.
 | last2 = Kough | first2 = J.
 | last3 = Vaituzis | first3 = Z.
 | last4 = Matthews | first4 = K.
 | title = Are Bt crops safe?
 | doi = 10.1038/nbt0903-1003
 | journal = Nature Biotechnology
 | volume = 21
 | issue = 9
 | pages = 1003–1009
 | year = 2003
 | pmid = 12949561
 | url = https://zenodo.org/record/1233343
 }}</ref>