NCERT Textbook: Applications of Recombinant DNA Technology | Biotechnology for Class 12 - NEET PDF Download

 Page 1


Recombinant DNA (rDNA) technology has revolutionised 
our life in various ways. In recent years breakthrough 
discoveries have provided solutions to many of the problems. 
These include establishing the identity of an individual, 
introduction of foreign genes into other organisms, 
diagnosis of many diseases and their treatment, production 
of therapeutic agents/molecules and so on. In this chapter, 
students will be acquainted with a few applications of rDNA 
technology, like DNA ??ngerprinting, developing transgenic 
organisms, gene therapy, recombinant vaccines and 
production of therapeutic agents/molecules.
4.1 DNA Fi Ngerpri Nti Ng As you are aware, chemical structure of every individual’s 
DNA is identical and is made up of four nitrogenous bases: 
A (Adenine), G (Guanine), C (Cytosine) and T (Thymine). 
The arrangement of these bases along the DNA strands 
is speci??c to an individual. The human genome consists 
of  3.2 × 10
9 
bp. However, there is very little uniqueness 
in the genetic makeup of humans. About 99.9% of the 
genome among humans is same and the remaining 0.1% 
of the genome consists of sites of inherited variations. It is 
these variations in DNA, which make each of us unique. 
Identifying these differences is helpful in determining the 
Applications of Recombinant
DNA Technology
4.1 DNA Fingerprinting
4.2 Transgenic 
Organism 
4.3 Gene Therapy 
4.4 Recombinant 
Vaccines
4.5 Therapeutic 
Agents/Molecules: 
Monoclonal 
antibodies, insulin 
and Growth 
Hormone
4 Chapter 
Chapter 4_App recombinant DNA Tec_New corrections.indd   67 23-01-2025   11:21:55
Reprint 2025-26
Page 2


Recombinant DNA (rDNA) technology has revolutionised 
our life in various ways. In recent years breakthrough 
discoveries have provided solutions to many of the problems. 
These include establishing the identity of an individual, 
introduction of foreign genes into other organisms, 
diagnosis of many diseases and their treatment, production 
of therapeutic agents/molecules and so on. In this chapter, 
students will be acquainted with a few applications of rDNA 
technology, like DNA ??ngerprinting, developing transgenic 
organisms, gene therapy, recombinant vaccines and 
production of therapeutic agents/molecules.
4.1 DNA Fi Ngerpri Nti Ng As you are aware, chemical structure of every individual’s 
DNA is identical and is made up of four nitrogenous bases: 
A (Adenine), G (Guanine), C (Cytosine) and T (Thymine). 
The arrangement of these bases along the DNA strands 
is speci??c to an individual. The human genome consists 
of  3.2 × 10
9 
bp. However, there is very little uniqueness 
in the genetic makeup of humans. About 99.9% of the 
genome among humans is same and the remaining 0.1% 
of the genome consists of sites of inherited variations. It is 
these variations in DNA, which make each of us unique. 
Identifying these differences is helpful in determining the 
Applications of Recombinant
DNA Technology
4.1 DNA Fingerprinting
4.2 Transgenic 
Organism 
4.3 Gene Therapy 
4.4 Recombinant 
Vaccines
4.5 Therapeutic 
Agents/Molecules: 
Monoclonal 
antibodies, insulin 
and Growth 
Hormone
4 Chapter 
Chapter 4_App recombinant DNA Tec_New corrections.indd   67 23-01-2025   11:21:55
Reprint 2025-26
Biotechnology XII 68
relatedness between two individuals. One way of achieving 
this is by DNA sequencing. However, sequencing and 
comparing DNA of individuals every time would not be 
feasible. Therefore, to study and compare the inherited 
variations in human DNA without sequencing, a new 
technique known as ‘DNA ??ngerprinting’ was developed 
by a British geneticist Sir Alec Jeffreys in 1984 at the 
University of Leicester.
More than 90% of the human genome consists of 
DNA which does not code for protein. Within the non-
coding regions of an individual’s genome, there exists short 
sequences of nucleotides which are repeated a number 
of times in tandem called STR 
(short tandem repeats) at a locus 
which are called VNTR (variable 
number tandem repeat). VNTRs 
are commonly subdivided into two 
principal families: microsatellites 
(repeated sequences of 1 to 9 
bp) and minisatellites (repeated 
sequences of 10 to 100 bp) as 
shown in Fig. 4.1. 
These sequences show a high degree of polymorphism 
(or variations) and form the basis of DNA ??ngerprinting. 
Furthermore, as the polymorphisms are inheritable from 
parent to offspring, DNA ??ngerprinting is the basis of 
paternity testing in case of disputes.
Fig. 4.2: DNA profiling to determine the child of a couple. In the above figure, the DNA profile of a child 
is compared with father and mother to confirm paternity. Here, father and mother are parents 
of child 1 but not of child 2.
Father Father Mother Mother Child 1 Child 1 Child 2
Fig. 4.1: Schematic representation of VNTRs in 3 alleles
VNTRs
Chapter 4_App recombinant DNA Tec_New corrections.indd   68 23-01-2025   11:21:55
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Page 3


Recombinant DNA (rDNA) technology has revolutionised 
our life in various ways. In recent years breakthrough 
discoveries have provided solutions to many of the problems. 
These include establishing the identity of an individual, 
introduction of foreign genes into other organisms, 
diagnosis of many diseases and their treatment, production 
of therapeutic agents/molecules and so on. In this chapter, 
students will be acquainted with a few applications of rDNA 
technology, like DNA ??ngerprinting, developing transgenic 
organisms, gene therapy, recombinant vaccines and 
production of therapeutic agents/molecules.
4.1 DNA Fi Ngerpri Nti Ng As you are aware, chemical structure of every individual’s 
DNA is identical and is made up of four nitrogenous bases: 
A (Adenine), G (Guanine), C (Cytosine) and T (Thymine). 
The arrangement of these bases along the DNA strands 
is speci??c to an individual. The human genome consists 
of  3.2 × 10
9 
bp. However, there is very little uniqueness 
in the genetic makeup of humans. About 99.9% of the 
genome among humans is same and the remaining 0.1% 
of the genome consists of sites of inherited variations. It is 
these variations in DNA, which make each of us unique. 
Identifying these differences is helpful in determining the 
Applications of Recombinant
DNA Technology
4.1 DNA Fingerprinting
4.2 Transgenic 
Organism 
4.3 Gene Therapy 
4.4 Recombinant 
Vaccines
4.5 Therapeutic 
Agents/Molecules: 
Monoclonal 
antibodies, insulin 
and Growth 
Hormone
4 Chapter 
Chapter 4_App recombinant DNA Tec_New corrections.indd   67 23-01-2025   11:21:55
Reprint 2025-26
Biotechnology XII 68
relatedness between two individuals. One way of achieving 
this is by DNA sequencing. However, sequencing and 
comparing DNA of individuals every time would not be 
feasible. Therefore, to study and compare the inherited 
variations in human DNA without sequencing, a new 
technique known as ‘DNA ??ngerprinting’ was developed 
by a British geneticist Sir Alec Jeffreys in 1984 at the 
University of Leicester.
More than 90% of the human genome consists of 
DNA which does not code for protein. Within the non-
coding regions of an individual’s genome, there exists short 
sequences of nucleotides which are repeated a number 
of times in tandem called STR 
(short tandem repeats) at a locus 
which are called VNTR (variable 
number tandem repeat). VNTRs 
are commonly subdivided into two 
principal families: microsatellites 
(repeated sequences of 1 to 9 
bp) and minisatellites (repeated 
sequences of 10 to 100 bp) as 
shown in Fig. 4.1. 
These sequences show a high degree of polymorphism 
(or variations) and form the basis of DNA ??ngerprinting. 
Furthermore, as the polymorphisms are inheritable from 
parent to offspring, DNA ??ngerprinting is the basis of 
paternity testing in case of disputes.
Fig. 4.2: DNA profiling to determine the child of a couple. In the above figure, the DNA profile of a child 
is compared with father and mother to confirm paternity. Here, father and mother are parents 
of child 1 but not of child 2.
Father Father Mother Mother Child 1 Child 1 Child 2
Fig. 4.1: Schematic representation of VNTRs in 3 alleles
VNTRs
Chapter 4_App recombinant DNA Tec_New corrections.indd   68 23-01-2025   11:21:55
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Applications of Recombinant DNA technology
69
We carry two different copies of every VNTR locus because 
we inherit one chromosome from mother and one from father. 
In simplest way, DNA ??ngerprinting can be performed using 
restriction digestion of DNA. This technique is referred to 
as Restriction Fragment Length Polymorphism (RFLP). In 
RFLP, after restriction enzyme digestion of individual’s DNA 
in speci??c regions, unique patterns are generated that are 
used for genetic analysis and identi??cation (Fig. 4.2).
Conceptually, the DNA ??ngerprinting shown in Fig. 4.2  
is correct but in reality, the identi??cation of individual bands 
on gel is dif??cult and therefore, hybridisation (Southern 
Hybridisation) using a VNTR probe is used. Hybridisation 
with VNTR probes produces a pattern of bands which 
are characteristic to every individual (Fig. 4.3). The steps 
involved in this technique are as follows:
1. DNA is isolated from different samples like blood, 
hair, skin, semen, buccal swab, etc. 
2. The collected DNA sample is cut into several 
fragments of different sizes using one or more 
restriction enzymes. 
Fig. 4.3: Steps involved in DNA Fingerprinting
Sample
Probe
nylon
membrane
DNA Transferred
to nylon membrane
Hybridi ation with s
labelled probe
DNA pattern
compared with
known subjects
Extracted
DNA
Restriction
digestion
Fragmented
DNA
Electrophoresis gel
S
1
S
2
gel
Chapter 4_App recombinant DNA Tec_New corrections.indd   69 23-01-2025   11:21:55
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Page 4


Recombinant DNA (rDNA) technology has revolutionised 
our life in various ways. In recent years breakthrough 
discoveries have provided solutions to many of the problems. 
These include establishing the identity of an individual, 
introduction of foreign genes into other organisms, 
diagnosis of many diseases and their treatment, production 
of therapeutic agents/molecules and so on. In this chapter, 
students will be acquainted with a few applications of rDNA 
technology, like DNA ??ngerprinting, developing transgenic 
organisms, gene therapy, recombinant vaccines and 
production of therapeutic agents/molecules.
4.1 DNA Fi Ngerpri Nti Ng As you are aware, chemical structure of every individual’s 
DNA is identical and is made up of four nitrogenous bases: 
A (Adenine), G (Guanine), C (Cytosine) and T (Thymine). 
The arrangement of these bases along the DNA strands 
is speci??c to an individual. The human genome consists 
of  3.2 × 10
9 
bp. However, there is very little uniqueness 
in the genetic makeup of humans. About 99.9% of the 
genome among humans is same and the remaining 0.1% 
of the genome consists of sites of inherited variations. It is 
these variations in DNA, which make each of us unique. 
Identifying these differences is helpful in determining the 
Applications of Recombinant
DNA Technology
4.1 DNA Fingerprinting
4.2 Transgenic 
Organism 
4.3 Gene Therapy 
4.4 Recombinant 
Vaccines
4.5 Therapeutic 
Agents/Molecules: 
Monoclonal 
antibodies, insulin 
and Growth 
Hormone
4 Chapter 
Chapter 4_App recombinant DNA Tec_New corrections.indd   67 23-01-2025   11:21:55
Reprint 2025-26
Biotechnology XII 68
relatedness between two individuals. One way of achieving 
this is by DNA sequencing. However, sequencing and 
comparing DNA of individuals every time would not be 
feasible. Therefore, to study and compare the inherited 
variations in human DNA without sequencing, a new 
technique known as ‘DNA ??ngerprinting’ was developed 
by a British geneticist Sir Alec Jeffreys in 1984 at the 
University of Leicester.
More than 90% of the human genome consists of 
DNA which does not code for protein. Within the non-
coding regions of an individual’s genome, there exists short 
sequences of nucleotides which are repeated a number 
of times in tandem called STR 
(short tandem repeats) at a locus 
which are called VNTR (variable 
number tandem repeat). VNTRs 
are commonly subdivided into two 
principal families: microsatellites 
(repeated sequences of 1 to 9 
bp) and minisatellites (repeated 
sequences of 10 to 100 bp) as 
shown in Fig. 4.1. 
These sequences show a high degree of polymorphism 
(or variations) and form the basis of DNA ??ngerprinting. 
Furthermore, as the polymorphisms are inheritable from 
parent to offspring, DNA ??ngerprinting is the basis of 
paternity testing in case of disputes.
Fig. 4.2: DNA profiling to determine the child of a couple. In the above figure, the DNA profile of a child 
is compared with father and mother to confirm paternity. Here, father and mother are parents 
of child 1 but not of child 2.
Father Father Mother Mother Child 1 Child 1 Child 2
Fig. 4.1: Schematic representation of VNTRs in 3 alleles
VNTRs
Chapter 4_App recombinant DNA Tec_New corrections.indd   68 23-01-2025   11:21:55
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Applications of Recombinant DNA technology
69
We carry two different copies of every VNTR locus because 
we inherit one chromosome from mother and one from father. 
In simplest way, DNA ??ngerprinting can be performed using 
restriction digestion of DNA. This technique is referred to 
as Restriction Fragment Length Polymorphism (RFLP). In 
RFLP, after restriction enzyme digestion of individual’s DNA 
in speci??c regions, unique patterns are generated that are 
used for genetic analysis and identi??cation (Fig. 4.2).
Conceptually, the DNA ??ngerprinting shown in Fig. 4.2  
is correct but in reality, the identi??cation of individual bands 
on gel is dif??cult and therefore, hybridisation (Southern 
Hybridisation) using a VNTR probe is used. Hybridisation 
with VNTR probes produces a pattern of bands which 
are characteristic to every individual (Fig. 4.3). The steps 
involved in this technique are as follows:
1. DNA is isolated from different samples like blood, 
hair, skin, semen, buccal swab, etc. 
2. The collected DNA sample is cut into several 
fragments of different sizes using one or more 
restriction enzymes. 
Fig. 4.3: Steps involved in DNA Fingerprinting
Sample
Probe
nylon
membrane
DNA Transferred
to nylon membrane
Hybridi ation with s
labelled probe
DNA pattern
compared with
known subjects
Extracted
DNA
Restriction
digestion
Fragmented
DNA
Electrophoresis gel
S
1
S
2
gel
Chapter 4_App recombinant DNA Tec_New corrections.indd   69 23-01-2025   11:21:55
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Biotechnology XII 70
3. The DNA fragments are then separated by agarose 
gel electrophoresis. The different sized DNA pieces 
are separated based on size.
4. The separated DNA on the gel is thus transferred 
to a nitrocellulose/nylon membrane. The nylon 
membrane is then exposed to UV radiation on UV 
transilluminator for three minutes or baked at 80°C 
for two hours to permanently attach DNA to the 
membrane.
5. Now, Southern hybridisation is performed using 
VNTR Probes (the labeled stretches of single-stranded 
DNA used to detect the presence of complementary 
target sequences). 
6. Finally, the hybridised DNA fragments are detected. 
7. The patterns of DNA bands are highly speci??c for 
each individual and can be used in forensics and 
paternity disputes.
Note: Polymerase Chain Reaction (PCR) is often used to increase the sensitivity of the 
technique as it ampli??es the DNA, irrespective of the amount of DNA.
Applications of DNA Fingerprinting
1. VNTR patterns are used to ascertain the paternity 
and maternity of a person given the fact that they are 
inherited from their parents. Since, these patterns 
are very speci??c, even a parental VNTR pattern 
can be reconstructed from their known offspring(s)  
VNTR patterns. Therefore, VNTR patterns of 
parent – child can be used to solve paternity and 
maternity cases.
2. DNA isolated from tissues like blood, hair, skin, 
semen, etc., from the scene of a crime is used for 
VNTR patterns analysis as evidence, where such 
a pattern of DNA isolate is compared with VNTR 
patterns of a criminal or suspect for establishing 
guilt or innocence. Hence, DNA ??ngerprinting helps 
in criminal identi??cation and forensic studies.
Chapter 4_App recombinant DNA Tec_New corrections.indd   70 23-01-2025   11:21:55
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Page 5


Recombinant DNA (rDNA) technology has revolutionised 
our life in various ways. In recent years breakthrough 
discoveries have provided solutions to many of the problems. 
These include establishing the identity of an individual, 
introduction of foreign genes into other organisms, 
diagnosis of many diseases and their treatment, production 
of therapeutic agents/molecules and so on. In this chapter, 
students will be acquainted with a few applications of rDNA 
technology, like DNA ??ngerprinting, developing transgenic 
organisms, gene therapy, recombinant vaccines and 
production of therapeutic agents/molecules.
4.1 DNA Fi Ngerpri Nti Ng As you are aware, chemical structure of every individual’s 
DNA is identical and is made up of four nitrogenous bases: 
A (Adenine), G (Guanine), C (Cytosine) and T (Thymine). 
The arrangement of these bases along the DNA strands 
is speci??c to an individual. The human genome consists 
of  3.2 × 10
9 
bp. However, there is very little uniqueness 
in the genetic makeup of humans. About 99.9% of the 
genome among humans is same and the remaining 0.1% 
of the genome consists of sites of inherited variations. It is 
these variations in DNA, which make each of us unique. 
Identifying these differences is helpful in determining the 
Applications of Recombinant
DNA Technology
4.1 DNA Fingerprinting
4.2 Transgenic 
Organism 
4.3 Gene Therapy 
4.4 Recombinant 
Vaccines
4.5 Therapeutic 
Agents/Molecules: 
Monoclonal 
antibodies, insulin 
and Growth 
Hormone
4 Chapter 
Chapter 4_App recombinant DNA Tec_New corrections.indd   67 23-01-2025   11:21:55
Reprint 2025-26
Biotechnology XII 68
relatedness between two individuals. One way of achieving 
this is by DNA sequencing. However, sequencing and 
comparing DNA of individuals every time would not be 
feasible. Therefore, to study and compare the inherited 
variations in human DNA without sequencing, a new 
technique known as ‘DNA ??ngerprinting’ was developed 
by a British geneticist Sir Alec Jeffreys in 1984 at the 
University of Leicester.
More than 90% of the human genome consists of 
DNA which does not code for protein. Within the non-
coding regions of an individual’s genome, there exists short 
sequences of nucleotides which are repeated a number 
of times in tandem called STR 
(short tandem repeats) at a locus 
which are called VNTR (variable 
number tandem repeat). VNTRs 
are commonly subdivided into two 
principal families: microsatellites 
(repeated sequences of 1 to 9 
bp) and minisatellites (repeated 
sequences of 10 to 100 bp) as 
shown in Fig. 4.1. 
These sequences show a high degree of polymorphism 
(or variations) and form the basis of DNA ??ngerprinting. 
Furthermore, as the polymorphisms are inheritable from 
parent to offspring, DNA ??ngerprinting is the basis of 
paternity testing in case of disputes.
Fig. 4.2: DNA profiling to determine the child of a couple. In the above figure, the DNA profile of a child 
is compared with father and mother to confirm paternity. Here, father and mother are parents 
of child 1 but not of child 2.
Father Father Mother Mother Child 1 Child 1 Child 2
Fig. 4.1: Schematic representation of VNTRs in 3 alleles
VNTRs
Chapter 4_App recombinant DNA Tec_New corrections.indd   68 23-01-2025   11:21:55
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Applications of Recombinant DNA technology
69
We carry two different copies of every VNTR locus because 
we inherit one chromosome from mother and one from father. 
In simplest way, DNA ??ngerprinting can be performed using 
restriction digestion of DNA. This technique is referred to 
as Restriction Fragment Length Polymorphism (RFLP). In 
RFLP, after restriction enzyme digestion of individual’s DNA 
in speci??c regions, unique patterns are generated that are 
used for genetic analysis and identi??cation (Fig. 4.2).
Conceptually, the DNA ??ngerprinting shown in Fig. 4.2  
is correct but in reality, the identi??cation of individual bands 
on gel is dif??cult and therefore, hybridisation (Southern 
Hybridisation) using a VNTR probe is used. Hybridisation 
with VNTR probes produces a pattern of bands which 
are characteristic to every individual (Fig. 4.3). The steps 
involved in this technique are as follows:
1. DNA is isolated from different samples like blood, 
hair, skin, semen, buccal swab, etc. 
2. The collected DNA sample is cut into several 
fragments of different sizes using one or more 
restriction enzymes. 
Fig. 4.3: Steps involved in DNA Fingerprinting
Sample
Probe
nylon
membrane
DNA Transferred
to nylon membrane
Hybridi ation with s
labelled probe
DNA pattern
compared with
known subjects
Extracted
DNA
Restriction
digestion
Fragmented
DNA
Electrophoresis gel
S
1
S
2
gel
Chapter 4_App recombinant DNA Tec_New corrections.indd   69 23-01-2025   11:21:55
Reprint 2025-26
Biotechnology XII 70
3. The DNA fragments are then separated by agarose 
gel electrophoresis. The different sized DNA pieces 
are separated based on size.
4. The separated DNA on the gel is thus transferred 
to a nitrocellulose/nylon membrane. The nylon 
membrane is then exposed to UV radiation on UV 
transilluminator for three minutes or baked at 80°C 
for two hours to permanently attach DNA to the 
membrane.
5. Now, Southern hybridisation is performed using 
VNTR Probes (the labeled stretches of single-stranded 
DNA used to detect the presence of complementary 
target sequences). 
6. Finally, the hybridised DNA fragments are detected. 
7. The patterns of DNA bands are highly speci??c for 
each individual and can be used in forensics and 
paternity disputes.
Note: Polymerase Chain Reaction (PCR) is often used to increase the sensitivity of the 
technique as it ampli??es the DNA, irrespective of the amount of DNA.
Applications of DNA Fingerprinting
1. VNTR patterns are used to ascertain the paternity 
and maternity of a person given the fact that they are 
inherited from their parents. Since, these patterns 
are very speci??c, even a parental VNTR pattern 
can be reconstructed from their known offspring(s)  
VNTR patterns. Therefore, VNTR patterns of 
parent – child can be used to solve paternity and 
maternity cases.
2. DNA isolated from tissues like blood, hair, skin, 
semen, etc., from the scene of a crime is used for 
VNTR patterns analysis as evidence, where such 
a pattern of DNA isolate is compared with VNTR 
patterns of a criminal or suspect for establishing 
guilt or innocence. Hence, DNA ??ngerprinting helps 
in criminal identi??cation and forensic studies.
Chapter 4_App recombinant DNA Tec_New corrections.indd   70 23-01-2025   11:21:55
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Applications of Recombinant DNA technology
71
3. DNA ??ngerprinting is also used to compare DNA 
extracts from fossils to modern day counter parts 
and therefore, ??nds great signi??cance in evolutionary 
biology studies.
4. DNA pro??le of people suffering from some particular 
disorder, or comparing it to a large number of people 
with and without the disorder helps to identify the 
DNA patterns in studying inherited disorders.
5. In addition to social security numbers, picture ID 
and other more routine methods, even the DNA 
pro??le (VNTR patterns) of an individual are also being 
proposed to be used as a sort of genetic barcode for 
personal identi??cation.
4.2 t r ANsge Nic Org ANism You must have heard about ‘Bt Cotton’ or ‘Rosie, the cow’, 
but have you ever wondered what these are? Are these 
naturally found in the environment? If not, then how have 
these been created? Or why these have been created at all? 
Both the examples mentioned above are a transgenic plant 
and animal, respectively. These have been produced by the 
introduction of new gene segments through the process 
of transgenesis and these are not naturally found in the 
environment. These have been created for the bene??t of 
human beings.
The process of insertion of a foreign gene (transgene) 
into the genome of an organism and its transmission 
and expression in the organism’s progeny is termed as 
transgenesis. The organisms carrying the transgene, are 
known as transgenic organisms or genetically modified 
organisms (GMOs).
4.2.1 Historical background
The ??rst genetically modi??ed organism was a bacterium 
made by Herbert Boyer and Stanley Cohen in 1973. In the 
subsequent year, it was followed by the engineering of ??rst 
transgenic animal (transgenic mice) by Rudolf Jaenisch 
and Beatrice Mintz in 1974. In 1994, Flavr Savr tomato 
was released as the ??rst genetically modi??ed (GM) food 
crop approved by the US Food and Drug Administration 
(USFDA).
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