Lecture 4 - Transgenic Animals: Applications | Biotechnology (Zoology) by ILLL, DU - Biotechnology Engineering (BT) PDF Download

 Page 1


 
 
  
 
 
 
 
 
 
 
 
 
 
Zoology 
Lesson: Transgenic Animals: Applications 
Lesson Developer: Dr Meena Yadav 
College /Department: Maitreyi College, 
 University of Delhi 
 
 
 
 
 
Page 2


 
 
  
 
 
 
 
 
 
 
 
 
 
Zoology 
Lesson: Transgenic Animals: Applications 
Lesson Developer: Dr Meena Yadav 
College /Department: Maitreyi College, 
 University of Delhi 
 
 
 
 
 
Transgenic Animals: Applications 
 
 
 
 Institute of Lifelong Learning, University of Delhi                     Page - 1 -  
 
 
Table of Contents 
? Introduction 
? The need for Transgenic Animals 
? Why therapeutic proteins are produced in transgenic livestock and not in microbes? 
? Possible mediums, other than milk, for production of recombinant proteins 
? Applications of transgenic animals 
? Transgenic and cloned animals for food/improved traits 
? Products/characters desired in transgenic animals 
? Milk 
? Improvement in disease resistance 
? Reproductive fitness 
? Wool and Hair fiber 
? Breeding of transgenic animals 
? Medical applications 
? Xenotransplantation 
? Blood replacement 
? Production of pharmaceuticals from Transgenic animals 
? Transgenic animals as disease models 
? Transgenic animals for disease control 
? Transgenic animals for environmental uses 
? Transgenic animals and human gene therapy 
? Other uses of Transgenic animals 
? Problems with drugs from Transgenic animals 
? Ethical issues of Transgenic animals 
? Summary 
? Exercise/Practice 
? Glossary 
? References/Bibliography/Further Reading 
 
Page 3


 
 
  
 
 
 
 
 
 
 
 
 
 
Zoology 
Lesson: Transgenic Animals: Applications 
Lesson Developer: Dr Meena Yadav 
College /Department: Maitreyi College, 
 University of Delhi 
 
 
 
 
 
Transgenic Animals: Applications 
 
 
 
 Institute of Lifelong Learning, University of Delhi                     Page - 1 -  
 
 
Table of Contents 
? Introduction 
? The need for Transgenic Animals 
? Why therapeutic proteins are produced in transgenic livestock and not in microbes? 
? Possible mediums, other than milk, for production of recombinant proteins 
? Applications of transgenic animals 
? Transgenic and cloned animals for food/improved traits 
? Products/characters desired in transgenic animals 
? Milk 
? Improvement in disease resistance 
? Reproductive fitness 
? Wool and Hair fiber 
? Breeding of transgenic animals 
? Medical applications 
? Xenotransplantation 
? Blood replacement 
? Production of pharmaceuticals from Transgenic animals 
? Transgenic animals as disease models 
? Transgenic animals for disease control 
? Transgenic animals for environmental uses 
? Transgenic animals and human gene therapy 
? Other uses of Transgenic animals 
? Problems with drugs from Transgenic animals 
? Ethical issues of Transgenic animals 
? Summary 
? Exercise/Practice 
? Glossary 
? References/Bibliography/Further Reading 
 
Transgenic Animals: Applications 
 
 
 
 Institute of Lifelong Learning, University of Delhi                     Page - 2 -  
 
 
INTRODUCTION 
Ever since humans started socializing, animal breeding and animal biotechnology has 
been practiced. Different ways of animal breeding, genetics and nutrition are thought to 
play an important role in selecting, propagating and managing the desirable and 
economically significant characteristics in livestock. Seeing the recent trends in advances 
in biotechnological tools, it can evidently be said that the livestock production will rely 
more heavily on these techniques to improve services to humans in future. Transgenic or 
genetically modified livestock and other emerging biotechnological techniques will 
definitely play major roles in production of high quality food from livestock. 
 
A transgenic animal can be defined as the animal whose DNA has been modified by 
adding a desired gene or DNA sequence from a suitable donor. This is done by genetic 
engineering technology in such a way that the desired gene is expressed and inherited 
by the progeny. There exist many techniques to produce transgenic animals, and all 
have their own advantages and disadvantages. Some of the common techniques in use 
are given in Fig. 1. 
Figure 1. Methods used for producing transgenic animals 
Source: ILLL in house 
 
Page 4


 
 
  
 
 
 
 
 
 
 
 
 
 
Zoology 
Lesson: Transgenic Animals: Applications 
Lesson Developer: Dr Meena Yadav 
College /Department: Maitreyi College, 
 University of Delhi 
 
 
 
 
 
Transgenic Animals: Applications 
 
 
 
 Institute of Lifelong Learning, University of Delhi                     Page - 1 -  
 
 
Table of Contents 
? Introduction 
? The need for Transgenic Animals 
? Why therapeutic proteins are produced in transgenic livestock and not in microbes? 
? Possible mediums, other than milk, for production of recombinant proteins 
? Applications of transgenic animals 
? Transgenic and cloned animals for food/improved traits 
? Products/characters desired in transgenic animals 
? Milk 
? Improvement in disease resistance 
? Reproductive fitness 
? Wool and Hair fiber 
? Breeding of transgenic animals 
? Medical applications 
? Xenotransplantation 
? Blood replacement 
? Production of pharmaceuticals from Transgenic animals 
? Transgenic animals as disease models 
? Transgenic animals for disease control 
? Transgenic animals for environmental uses 
? Transgenic animals and human gene therapy 
? Other uses of Transgenic animals 
? Problems with drugs from Transgenic animals 
? Ethical issues of Transgenic animals 
? Summary 
? Exercise/Practice 
? Glossary 
? References/Bibliography/Further Reading 
 
Transgenic Animals: Applications 
 
 
 
 Institute of Lifelong Learning, University of Delhi                     Page - 2 -  
 
 
INTRODUCTION 
Ever since humans started socializing, animal breeding and animal biotechnology has 
been practiced. Different ways of animal breeding, genetics and nutrition are thought to 
play an important role in selecting, propagating and managing the desirable and 
economically significant characteristics in livestock. Seeing the recent trends in advances 
in biotechnological tools, it can evidently be said that the livestock production will rely 
more heavily on these techniques to improve services to humans in future. Transgenic or 
genetically modified livestock and other emerging biotechnological techniques will 
definitely play major roles in production of high quality food from livestock. 
 
A transgenic animal can be defined as the animal whose DNA has been modified by 
adding a desired gene or DNA sequence from a suitable donor. This is done by genetic 
engineering technology in such a way that the desired gene is expressed and inherited 
by the progeny. There exist many techniques to produce transgenic animals, and all 
have their own advantages and disadvantages. Some of the common techniques in use 
are given in Fig. 1. 
Figure 1. Methods used for producing transgenic animals 
Source: ILLL in house 
 
Transgenic Animals: Applications 
 
 
 
 Institute of Lifelong Learning, University of Delhi                     Page - 3 -  
 
 
 
Value Addition: Do you know 
Heading Text: The OncoMouse 
Body Text: The OncoMouse was created by scientists at Harvard University 
by genetic engineering, which they later patented. This mouse carries a gene 
that promotes the development of various human cancers. Thus, it can be used 
to study the underlying mechanisms of cancer so that a possible cure could be 
found in future. It is also known as the Harvard mouse!!!!! 
Source: http://www.actionbioscience.org/biotechnology 
 
 
Though, mouse has been an excellent model organism to study various human diseases 
but since the livestock are comparatively more closely related to humans 
phylogenetically, they seem to have more similarity with humans. So, transgenic cattle 
might have more potential if used as animal models as compared to transgenic mouse. 
However, the methods used to generate transgenic cattle are similar to those used for 
transgenic mice (Figure 2). 
 
The steps in producing transgenic cattle are: 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Collection of oocytes (from slaughter houses) 
In vitro maturation 
 
In vitro fertilization (with bull semen) 
 
Centrifugation of eggs (to concentrate yolk, which 
otherwise prevents male pronuclei from being seen 
under the microscope) 
 
In vitro development of embryos (till blastocyst) 
 
DNA microinjection into male pronuclei 
 
Embryo implantation in foster mother (nonsurgical) 
Screening of offspring for transgene 
 
Page 5


 
 
  
 
 
 
 
 
 
 
 
 
 
Zoology 
Lesson: Transgenic Animals: Applications 
Lesson Developer: Dr Meena Yadav 
College /Department: Maitreyi College, 
 University of Delhi 
 
 
 
 
 
Transgenic Animals: Applications 
 
 
 
 Institute of Lifelong Learning, University of Delhi                     Page - 1 -  
 
 
Table of Contents 
? Introduction 
? The need for Transgenic Animals 
? Why therapeutic proteins are produced in transgenic livestock and not in microbes? 
? Possible mediums, other than milk, for production of recombinant proteins 
? Applications of transgenic animals 
? Transgenic and cloned animals for food/improved traits 
? Products/characters desired in transgenic animals 
? Milk 
? Improvement in disease resistance 
? Reproductive fitness 
? Wool and Hair fiber 
? Breeding of transgenic animals 
? Medical applications 
? Xenotransplantation 
? Blood replacement 
? Production of pharmaceuticals from Transgenic animals 
? Transgenic animals as disease models 
? Transgenic animals for disease control 
? Transgenic animals for environmental uses 
? Transgenic animals and human gene therapy 
? Other uses of Transgenic animals 
? Problems with drugs from Transgenic animals 
? Ethical issues of Transgenic animals 
? Summary 
? Exercise/Practice 
? Glossary 
? References/Bibliography/Further Reading 
 
Transgenic Animals: Applications 
 
 
 
 Institute of Lifelong Learning, University of Delhi                     Page - 2 -  
 
 
INTRODUCTION 
Ever since humans started socializing, animal breeding and animal biotechnology has 
been practiced. Different ways of animal breeding, genetics and nutrition are thought to 
play an important role in selecting, propagating and managing the desirable and 
economically significant characteristics in livestock. Seeing the recent trends in advances 
in biotechnological tools, it can evidently be said that the livestock production will rely 
more heavily on these techniques to improve services to humans in future. Transgenic or 
genetically modified livestock and other emerging biotechnological techniques will 
definitely play major roles in production of high quality food from livestock. 
 
A transgenic animal can be defined as the animal whose DNA has been modified by 
adding a desired gene or DNA sequence from a suitable donor. This is done by genetic 
engineering technology in such a way that the desired gene is expressed and inherited 
by the progeny. There exist many techniques to produce transgenic animals, and all 
have their own advantages and disadvantages. Some of the common techniques in use 
are given in Fig. 1. 
Figure 1. Methods used for producing transgenic animals 
Source: ILLL in house 
 
Transgenic Animals: Applications 
 
 
 
 Institute of Lifelong Learning, University of Delhi                     Page - 3 -  
 
 
 
Value Addition: Do you know 
Heading Text: The OncoMouse 
Body Text: The OncoMouse was created by scientists at Harvard University 
by genetic engineering, which they later patented. This mouse carries a gene 
that promotes the development of various human cancers. Thus, it can be used 
to study the underlying mechanisms of cancer so that a possible cure could be 
found in future. It is also known as the Harvard mouse!!!!! 
Source: http://www.actionbioscience.org/biotechnology 
 
 
Though, mouse has been an excellent model organism to study various human diseases 
but since the livestock are comparatively more closely related to humans 
phylogenetically, they seem to have more similarity with humans. So, transgenic cattle 
might have more potential if used as animal models as compared to transgenic mouse. 
However, the methods used to generate transgenic cattle are similar to those used for 
transgenic mice (Figure 2). 
 
The steps in producing transgenic cattle are: 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Collection of oocytes (from slaughter houses) 
In vitro maturation 
 
In vitro fertilization (with bull semen) 
 
Centrifugation of eggs (to concentrate yolk, which 
otherwise prevents male pronuclei from being seen 
under the microscope) 
 
In vitro development of embryos (till blastocyst) 
 
DNA microinjection into male pronuclei 
 
Embryo implantation in foster mother (nonsurgical) 
Screening of offspring for transgene 
 
Transgenic Animals: Applications 
 
 
 
 Institute of Lifelong Learning, University of Delhi                     Page - 4 -  
 
 
Figure 2: Steps in the development of transgenic cattle by DNA 
microinjection  
Source: Author 
 
The Need for Transgenic Animals 
 
The practice of improving breeds of cattle is many centuries old. But with the advent of 
transgenic technology, the idea of getting superior quality breeds can be achieved in a 
much less time as compared to traditional methods. Also, the constraints of sexual 
incompatibility are removed by using genetic engineering technology because genes 
from any source can be inserted in the transgenic animals. Transgenic animals are of 
immense use for human race: 
? Transgenic animals are useful for humans more specifically for economic reasons. 
First, transgenic cattle and birds can be created to produce more meat to cater to 
increased demand for food. 
? Transgenic cattle can be produced for increased milk production and also for secretion 
of particular human proteins. These proteins can be isolated from milk and purified to 
be used in treatment of many diseases. 
? Transgenic animals can also act as model organisms for study of mechanisms of 
several human diseases and their possible cures. 
? The physiological systems of humans can be better understood by studying the same 
in transgenic animals. 
? Apart from food, several other desired products can be obtained from transgenic 
animals and also the quality of these products can be monitored and changed from 
time to time. 
The procedure for producing transgenic mice/cattle is lengthy, burdensome and quite 
expensive but the technology is cost-effective because once a transgenic animal is 
produced, it can reproduce and pass the cloned gene to its progeny. 
 
 
Why therapeutic proteins are produced in transgenic livestock and 
not in microbes? 
 
The eukaryotic system is considerably different from the prokaryotic system as far as the 
nature and variety of proteins produced are concerned. Bacteria cannot synthesize 
complex proteins found in eukaryotic system because the eukaryotes have different and 
more complex post-translational modification machinery to fold the polypeptides into 
desired active forms in vivo. In the mammalian cells the protein is folded and processed 
properly. The expression of genes for such proteins in transgenic animals could be an 
alternative and cost-effective method. 
 
Although many proteins have been produced in blood of transgenic animals and eggs of 
transgenic chickens, but the use of farm animals such as cows and sheep is more 
rewarding, because they can be manipulated to produce more milk and the cloned gene 
can be attached to the promoter of ß-lactoglobulin gene of the animal. So, the desired 
protein will always be present in the secreted milk. The regulatory sequences from the 
genes of proteins found in milk have been cloned and can be used to control the 
expression of recombinant genes in transgenic animals (Figure 3).  
 
The recombinant protein is necessarily secreted in milk of transgenic cattle as their 
promoter is active in mammary tissues. Milk can be produced continuously during 
animal?s adult life, which results in a high yield of the protein. For example, an average