Application of genomics in animals

Application of Genomics
in Animals

 What is genomics?
POINTS TO COVER
How do we use genomics?
Application
Animal Cloning
Genetic engineering
Livestock Breeding Industry
Transgenic Animals
Gene therapy
Superovulation
Summary

What is genomics?
• Study of how the genome (DNA) of any
species is organized and expressed as
traits
• New technologies allow examination of an
organism’s genome as a whole rather
than 1 gene at a time
• Livestock and poultry genomes sequenced
to understand how various genes function
(functional genomics)

How do we use genomics?
 Identify DNA sequences associated with
disease resistance and production traits
 Animals can be evaluated as soon as
DNA can be obtained (even before birth)
 Best animals to be parents can be
determined earlier and more accurately

Application
 Increase rate of genetic improvement
 Detect abnormalities
 Improve understanding of mechanisms of
genetic control
 Determine parentage
 Identify superior animals early

Animal Cloning:
To Clone, or not to Clone
Dolly

Cloning
Definition: The process of making
identical genomic copies of
an original animal.
Encyclopedia Britannica: An individual
organism that was grown from a single
body cell of its parent and that is
genetically identical to it.

Stage 1
Cell collected from a sheep’s
udder.
Nucleus is removed from
unfertilized egg of second sheep.
Stage 2

Stage 3
Udder cell is inserted into egg
with no nucleus.
Stage 4
Insertion is successful

Stage 5
Electrical charge is supplied.

Stage 6
Cells begin to divide.

The simple addition, deletion,
or manipulation of a single trait
in an organism to create a
desired change.
Genetic Engineering

The process of creating transgenetic animals involves
three major steps:
1. Obtaining embryos
2. Microinjectioing embryos
3. Culturing and transferring zygotes
Transgenetic integration- is expressed by the animal of
that desired trait.

Agriculture
 Genetically Modified
Chickens That Don't
Transmit Bird Flu
 New gene makes a
small "decoy"
molecule that mimics
part of the bird flu
virus
 Virus can’t replicate

 Seedstock Producers
 Produces animals for breeding purposes
 Sire producing herds
 Dam producing herds

 Commercial Producers
 Animals are intended for entering the food
chain.
 Many times buy herd sires
 May or may not produce replacement
females.

Transgenic Animals
Transgenesis
process of introducing foreign or exogenous
DNA into an animal’s genome
Transgene
DNA introduced
Mice
Cows
Fish
Birds
Sheep
Goats

Why Transgenesis?
•Improve genetic Features of domesticated Animals
•Provide animal models for study of human diseases
•Pharming
using farm animals for production of human pharmaceuticals
-mammary glands
•Study the genes regulation, development of animals

How to Get the Transgene
Inserted
 Retroviral Vectors
 Microinjection
 Embryonic stem cells

Fig : The production of transgenic animals by
microinjection of DNA into fertilized eggs.

Health Care
 Insulin, growth hormone,
and blood anti-clotting
factors may soon be or
have already been
obtained from the milk of
transgenic cows, sheep,
or goats.
 Human gene is put into
the animal genome and
the protein can be found
in the milk.

A. What is gene therapy? Why is it
used?
 Gene therapy = Introduction of normal genes into cells
that contain defective genes to reconstitute a missing
protein product
 GT is used to correct a deficient phenotype so that
sufficient amounts of a normal gene product are
synthesized  to improve a genetic disorder

Limitations of Gene Therapy
 Gene delivery
 Limited tropism of viral vectors
 Dependence on cell cycle by some viral vectors (i.e.
mitosis required)
 Duration of gene activity
 Non-integrating delivery will be transient (transient
expression)
 Integrated delivery will be stable

Ectogenesis or out-of-the-body-
pregnancy
 Most arguments in favour of abortions rely heavily on the
biological fact that the fetus develops inside the female body.
 Most arguments for the present legal situation in Western
countries that women alone decide on whether or not to
continue the pregnancy rest on the same biological fact.
THE CASE OF ECTOGENESIS

Superovulation
 Treatment of a female with gonadotropins (generally
FSH) to increase the number of oocytes that are
selected to become dominant follicles and ovulate
 a typical treatment response in cattle would be 8 to 10 ovulations

Superovulation Procedures
 Hormones used for Superovulation
 FSH (follicle stimulating hormone)
 [Short half-life ~2 hours]
 Used for commercial SOET
 PMSG (pregnant mare serum gonadotropin;
eCG)
 [Long half-life ~ 2 - 4 days]
 Not approved for use in commercial SOET in the
US. Used frequently for research in Europe.

2. Superovulation of donor female
Goal: hyperstimulate ovaries with gonadotropins
Reason: provide higher than normal numbers of follicles that
will ovulate
How: inject donor with FSH
Steps of Embryo Transfer in Cows

Summary
 Genomic selection used extensively in
dairy cattle breeding
 High quality genotypes support detection
Genomics is revolutionizing animal
breeding
 Of parentage and other errors
 International collaboration has been
important for the success

Application of genomics in animals

Application of genomics in animals

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Application of genomics in animals