Transcript Unit 3: Genetics and Animal Breeding

UNIT 3: GENETICS AND ANIMAL
BREEDING
OBJECTIVES
3.1 Define Terms
 3.2 Discuss Mendel’s contributions to the study
of genetics
 3.3 Identify the parts of and explain the
functions of cells, chromosomes, and genes
 3.4 Differentiate between genotype and
phenotype
 3.5 Compare purebred breeding and
crossbreeding

OBJECTIVES
3.6 Identify factors to consider in selecting
breeding animals
 3.7 Describe reproduction processes in
agricultural animals
 3.8 Explain artificial insemination and identify
its advantages and disadvantages
 3.9 Discuss genetic engineering and its effect
on animal agriculture

3.1 DEFINE TERMS
1. cell—the basic unit of life
2. chromosome—a strand of genetic material that
contains genetic code
3. crossbreeding—the breeding of two different
pure breeds
4. gene—a unit of inheritance composed of DNA
3.1 DEFINE TERMS
5. genetics—the study of heredity
6. genotype—genetic makeup of an animal
7. heredity—the passing of traits from parents to
offspring
8. phenotype—the outward expression of a gene
3.1 DEFINE TERMS
9. purebred breeding—the breeding of animals
within the same breed
10. reproduction—the process by which new
organisms are derived normally involving the
union of the male and female sex cells
3.2 DISCUSS MENDEL’S CONTRIBUTIONS TO THE
STUDY OF GENETICS
WHY IS AN UNDERSTANDING OF GENETICS IMPORTANT, AND
WHAT WAS THE IMPACT OF GREGOR MENDEL’S
DEVELOPMENT OF THE BASIC PRINCIPLES OF HEREDITY?
Genetics is the study of the laws and
processes of biological inheritance.
 A. The study of genetics is concerned with
the transfer of traits.
 1. Gregor Mendel
discovered
that these
traits are
inherited
through units
called
genes.

WHY IS AN UNDERSTANDING OF GENETICS IMPORTANT, AND
WHAT WAS THE IMPACT OF GREGOR MENDEL’S
DEVELOPMENT OF THE BASIC PRINCIPLES OF HEREDITY?

2. Mendel further discovered that genes
were found in pairs, with half of the
inherited traits coming from the father and
half from the mother.
 This
passing of traits from parents to offspring
is called heredity.

3. Not all differences in animals are caused
by genetics.
 Some
are caused by the environment, or the
conditions in which the animal is raised.
WHY IS AN UNDERSTANDING OF GENETICS IMPORTANT, AND
WHAT WAS THE IMPACT OF GREGOR MENDEL’S
DEVELOPMENT OF THE BASIC PRINCIPLES OF HEREDITY?
B. A chromosome is a tiny, threadlike part in
a cell that contains the genetic material.
 1. Chromosomes are found in the nucleus
of cells.

 The
genetic material found in the chromosomes
is called the genome of the organism.
 When animals mate, the genome of the
offspring is a combination of the traits from the
mother and the father.
WHY IS AN UNDERSTANDING OF GENETICS IMPORTANT, AND
WHAT WAS THE IMPACT OF GREGOR MENDEL’S
DEVELOPMENT OF THE BASIC PRINCIPLES OF HEREDITY?

2. All the cells within the animal are
genetically identical.
 Each
cell contains identical numbers of
chromosomes.
 The number found in a cell varies between
species.

3. Chromosomes are made of DNA, or
deoxyribonucleic acid, which contains
genes.
 DNA
is a protein-like nucleic acid that controls
inheritance.
WHY IS AN UNDERSTANDING OF GENETICS IMPORTANT, AND
WHAT WAS THE IMPACT OF GREGOR MENDEL’S
DEVELOPMENT OF THE BASIC PRINCIPLES OF HEREDITY?

4. Each DNA molecule consists of
two strands shaped as a double
helix, or spiral structure.
 These
strands are nucleotides bonded
together by pairs of nitrogen bases.
 The nucleotides are made up of sugar
molecules held together by
phosphates.
 There are four nitrogen bases found in
DNA: cytosine, guanine, adenine, and
thymine.
WHY IS AN UNDERSTANDING OF GENETICS IMPORTANT, AND
WHAT WAS THE IMPACT OF GREGOR MENDEL’S
DEVELOPMENT OF THE BASIC PRINCIPLES OF HEREDITY?

5. The genetic code is the sequence of
nitrogen bases in the DNA molecule.
 This
sequence code is for amino acids and
proteins.
 The ability of DNA to
replicate itself allows for
the molecule to pass
genetic information from
one
cell generation to the next.
3.3 IDENTIFY THE PARTS OF AND EXPLAIN THE
FUNCTIONS OF CELLS, CHROMOSOMES, AND
GENES
WHAT ARE THE PARTS OF AN ANIMAL CELL, AND
WHAT ARE THE FUNCTIONS
OF THOSE PARTS?
Cells of all organisms have the same basic
makeup, or structure.
 Differences do occur, however, between the
cells of plants and animals.
 A. Animal cell components:
 1. The cell membrane is the outside
covering of the cell. It is made of a thin layer
of lipids (fats).

 The
functions of the cell membrane are:
WHAT ARE THE PARTS OF AN ANIMAL CELL, AND
WHAT ARE THE FUNCTIONS
OF THOSE PARTS?

a. To separate the cell contents from the
external environment.
 b.
To allow raw materials (carbohydrates and
proteins) to enter the cell.
 c. To allow newly made proteins and waste to
exit the cell.
WHAT ARE THE PARTS OF AN ANIMAL CELL, AND
WHAT ARE THE FUNCTIONS
OF THOSE PARTS?

2. The nucleus is the “brain” of the cell.
 The
nucleus controls all the cell’s activity.
 It is surrounded by the nuclear membrane,
which functions similarly to the cell membrane.
 The nucleus also contains chromosomes, which
are small strands of genetic material.
WHAT ARE THE PARTS OF AN ANIMAL CELL, AND
WHAT ARE THE FUNCTIONS
OF THOSE PARTS?



3. Cytoplasm is a jellylike substance between the
cell membrane and the nuclear membrane.
It contains several specialized structures called
organelles.
a. The endoplasmic reticulum is a network of
membranes that connects the cell membrane to
the nucleus.


There are two sections of the endoplasmic reticulum.
Each section has its own function.
WHAT ARE THE PARTS OF AN ANIMAL CELL, AND
WHAT ARE THE FUNCTIONS
OF THOSE PARTS?
 (1)
The smooth endoplasmic reticulum is the
site for the production of lipids (fats) and
hormones.
 (2) The rough endoplasmic reticulum is the site
for the production of proteins.
WHAT ARE THE PARTS OF AN ANIMAL CELL, AND
WHAT ARE THE FUNCTIONS
OF THOSE PARTS?

b. Mitochondria are small, egg-shaped organelles
that manufacture adenosine triphosphate (ATP).



ATP is used as an energy source for the cell.
It converts food into energy through cellular respiration.
c. Lysosomes are round organelles that cause the
digestion of proteins through the release of
enzymes.

These are made by the Golgi apparatus.
WHAT ARE THE PARTS OF AN ANIMAL CELL, AND
WHAT ARE THE FUNCTIONS
OF THOSE PARTS?

d. The Golgi apparatus consists of flattened
membrane sacs that receive substances
transported from the endoplasmic
reticulum.
 It
also stores the substances and alters their
chemical structure.
3.4 DIFFERENTIATE BETWEEN GENOTYPE AND
PHENOTYPE
HOW DO WE PREDICT THE GENOTYPES AND
PHENOTYPES FROM MONOHYBRID AND DIHYBRID
CROSSES BY USING THE PUNNETT SQUARE?
Resulting offspring of reproduction
have both genotype and phenotype
heredity.
 A. Genotype is the actual genetic
code.

 It
controls physical and performance
traits.
 The genotype of an organism cannot be
changed by environmental factors.
HOW DO WE PREDICT THE GENOTYPES AND
PHENOTYPES FROM MONOHYBRID AND DIHYBRID
CROSSES BY USING THE PUNNETT SQUARE?

B. Phenotype is the organism’s
physical or outward appearance.
 This
is the part of the
genotype the organism
expresses or shows.
 In some instances,
phenotype may be
altered by the
environment.
organism’s
HOW DO WE PREDICT THE GENOTYPES AND
PHENOTYPES FROM MONOHYBRID AND DIHYBRID
CROSSES BY USING THE PUNNETT SQUARE?
C. A homozygous organism is one having
similar alleles, or genes, on the DNA
molecule for a particular trait, while a
heterozygous organism is one having
different alleles for a particular trait.
 D. The Punnett square is a useful tool to
help determine both the genotype and
phenotype from animal crosses.

3.5 COMPARE PUREBRED BREEDING AND
CROSSBREEDING
WHAT ARE SOME OF THE COMMON
BREEDING SYSTEMS USED IN
LIVESTOCK PRODUCTION?
The system of breeding to be used by a
producer depends on the kind of livestock
operation.
 There are two basic systems of breeding
used in livestock production, and there
are several variations of each system
available for producers to utilize.
 The two basic systems are
straightbreeding and crossbreeding.

WHAT ARE SOME OF THE COMMON
BREEDING SYSTEMS USED IN
LIVESTOCK PRODUCTION?

A. Straightbreeding is mating animals of
the same breed.
 There
are several variations
of this system.
 Some of the most common
are purebred breeding,
inbreeding, outcrossing,
and grading up.
WHAT ARE SOME OF THE COMMON
BREEDING SYSTEMS USED IN
LIVESTOCK PRODUCTION?

1. A purebred animal is an animal of a
breed.
 Both
parents of the animal must have been
purebred.
 The production of
purebred animals is
a specialized
business.
 These animals
provide the foundation stock for
crossbreeding to produce market animals.
WHAT ARE SOME OF THE COMMON
BREEDING SYSTEMS USED IN
LIVESTOCK PRODUCTION?

2. Inbreeding is the mating of related
animals.
 This
increases the
genetic purity of the stock
produced.
 The pairing of the same
genes is increased, and
offspring become more
genetically homozygous.
 There are two types of inbreeding.
WHAT ARE SOME OF THE COMMON
BREEDING SYSTEMS USED IN
LIVESTOCK PRODUCTION?
 a.
Closebreeding is the most intensive form
of inbreeding, in which the animals being
mated are very closely related and can be
traced back to more than one common
ancestor.
 b. Linebreeding refers to
mating animals that are
more distantly related and
can be traced back to just
one common ancestor.
WHAT ARE SOME OF THE COMMON
BREEDING SYSTEMS USED IN
LIVESTOCK PRODUCTION?

3. Outcrossing is the mating of animals of
different families within the same breed.
 The
purpose of outcrossing is to bring into the
breeding program traits that are desirable but
not present in the original animals.

4. Grading up is the mating of purebred
sires to grade females.
A
grade animal is any animal not eligible for
registry as a purebred.
 This is done as a less-expensive way to
improve the quality of animals on a farm or
ranch.
WHAT ARE SOME OF THE COMMON
BREEDING SYSTEMS USED IN
LIVESTOCK PRODUCTION?

B. Crossbreeding is the mating of two
animals from different breeds.
 The
resulting offspring is a hybrid.
 This generally results in improved traits in the
offspring.
 Superior traits that result
from crossbreeding are
called hybrid vigor or
heterosis.
3.6 IDENTIFY FACTORS TO CONSIDER IN
SELECTING BREEDING ANIMALS
WHAT IS AN EPD?
EPD stands for Expected Progeny Difference.
 It is the measure of the degree of difference
between progeny of the bull and the progeny of
the average bull of the breed the trait is being
measured from.

EPD EXAMPLE
COMMON EPD TITLES






BW (Birth Weight)
WW (Weaning Weight)
YW (Yearling Weight)
MILK
CE (Calving Ease)
CED (Calving Ease
Direct) Predicts calving
ease of a sire when
mated to heifers.




CW (Carcass Weight)
DOC (Docility)
MW (Mature Weight)
MH (Mature Height)
BOVINE ELITE

EPD Comparison
3.7 DESCRIBE REPRODUCTION PROCESSES IN
AGRICULTURAL ANIMALS
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN MALE MAMMALS? WHAT
ARE THE FUNCTIONS OF THOSE ORGANS?
To have a successful livestock operation, a
producer must have an understanding of the
various reproductive organs
and their functions.
 In most cases, a livestock
operation will have only a
limited number of males available for
breeding.
 The male reproductive system contains
several interconnected parts that must all
work together for successful mating.

WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN MALE MAMMALS? WHAT
ARE THE FUNCTIONS OF THOSE ORGANS?
Some of the major organs found in the
male mammal reproductive system are:
 A. Testicles—The testicles produce sperm,
the male sex cells (also called
spermatozoa).



They also produce a hormone called testosterone
that causes the appearance and behavior of the
animal to be masculine.
Two testicles are present in male mammals.
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN MALE MAMMALS? WHAT
ARE THE FUNCTIONS OF THOSE ORGANS?

B. Epididymis—The epididymis is the
storage site for sperm cells.



From the testicle,
cells enter the
mature.
Sperm can fertilize a
female’s ova (female
sex cell) as it travels
through the epididymis.
A separate epididymis
is attached to each testicle.
these
epididymis to
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN MALE MAMMALS? WHAT
ARE THE FUNCTIONS OF THOSE ORGANS?

C. Scrotum—The scrotum is a two-lobed
sac that contains and protects the two
testicles.


It also regulates the temperature of the testicles,
which is lower than the body temperature.
When the environment temperature is low, the
scrotum contracts, pulling the testicles toward the
body and its warmth.
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN MALE MAMMALS? WHAT
ARE THE FUNCTIONS OF THOSE ORGANS?


When the environmental temperature is high, the
scrotum relaxes, permitting the testicles to drop away
from the body.
Maintaining the correct temperature is critical
because extreme temperatures (too hot or too cold)
can affect the production and vitality of sperm.
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN MALE MAMMALS? WHAT
ARE THE FUNCTIONS OF THOSE ORGANS?
D. Vas deferens—The vas deferens is
essentially a transportation tube that carries
the sperm-containing fluid from each
epididymis to the urethra.
 E. Urethra—The urethra
is a large, muscular canal
extending from the urinary
bladder.


Both semen and urine move through the urethra
to the end of the penis.
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN MALE MAMMALS? WHAT
ARE THE FUNCTIONS OF THOSE ORGANS?
F. Accessory sex glands—These are several
glands that add volume and nutrition to the
sperm-rich fluid coming from the epididymis.
 G. Seminal vesicles—The seminal vesicles
open into the urethra.



They produce a fluid that protects and transports
the sperm.
H. Prostate gland—The prostate gland is near
the urethra and the bladder.

It produces a fluid that is mixed with the seminal
fluid.
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN MALE MAMMALS? WHAT
ARE THE FUNCTIONS OF THOSE ORGANS?

I. Cowper’s gland—The cowper’s gland
produces a fluid that moves down the
urethra ahead of the seminal fluid.
 This
fluid cleans and neutralizes the urethra,
which helps protect the sperm as they move
through the urethra.
 The mixture of the
seminal and prostate
fluid and the sperm
is called semen.
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN MALE MAMMALS? WHAT
ARE THE FUNCTIONS OF THOSE ORGANS?

J. Penis—The penis deposits the semen
within the female reproductive system.



The urethra in the penis is surrounded by spongy
tissue that fills with blood when the male is sexually
aroused, which causes an erection that is necessary
for copulation (mating) to occur.
The sigmoid flexure (found in bulls, rams, and boars)
and the retractor muscle extend the penis from the
sheath, which is a tubular fold of skin.
Horses and other mammals do not have a sigmoid
flexure.
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN FEMALE MAMMALS? WHAT ARE
THE FUNCTIONS OF THOSE ORGANS?
Like males, female mammals have a
complex system of organs that compose
the reproductive system.
 It is important that those
interested in animal
production be familiar with
these various organs and
their functions.
 Some of the major organs that compose
the female reproductive tract are:

WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN FEMALE MAMMALS? WHAT ARE
THE FUNCTIONS OF THOSE ORGANS?

A. Ovary—The ovary produces female
gametes, which are sex cells that can
unite with other sex cells.
 These
are called ova (eggs).
 A female mammal will typically have two
ovaries, which also produce the female sex
hormones: estrogen and progesterone.
 Within each ovary, there are hundreds of tiny
follicles or cavities.
 The ova are produced in the follicles.
 Each ovum is the largest single cell in the
body.
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN FEMALE MAMMALS? WHAT ARE
THE FUNCTIONS OF THOSE ORGANS?

B. Oviducts—The oviducts are two tubes
that carry the ova from the ovaries to the
uterus.
 The
oviducts are also called the fallopian
tubes.
 The oviducts are close, but they are not
attached to the ovaries.
 The funnel-shaped end of each oviduct that is
close to the ovary is the infundibulum.
 At ovulation the follicle ruptures, releasing an
ovum that is caught by the infundibulum.
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN FEMALE MAMMALS? WHAT ARE
THE FUNCTIONS OF THOSE ORGANS?
 After
copulation, sperm move through the
uterus to the oviduct.
 Fertilization of the ovum occurs in the upper
end of the oviduct.
 The zygote, or
fertilized egg cell,
moves to the
uterus about two
to four days after
fertilization.
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN FEMALE MAMMALS? WHAT ARE
THE FUNCTIONS OF THOSE ORGANS?

C. Uterus—The uterus of mammals is a Yshaped structure consisting of the body,
two uterine horns, and the
cervix.
 The
size and shape
of the uterus varies
among mammals.
 The upper part of the uterus consists of the
two uterine horns that develop into the
oviducts or fallopian tubes.
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN FEMALE MAMMALS? WHAT ARE
THE FUNCTIONS OF THOSE ORGANS?
 Mammals
that normally produce large numbers
of offspring at each breeding have relatively
large horns and a small body.
 Those mammals that normally
produce single offspring or
twins have smaller horns and
a larger body.
 In most mammals, pregnancy normally occurs
in the uterine horns.
 In horses, however, pregnancy normally occurs
in the body of the uterus.
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN FEMALE MAMMALS? WHAT ARE
THE FUNCTIONS OF THOSE ORGANS?
 In
all mammals, the fetus grows within the
uterus, where it remains until parturition or
birth.
 The cervix is the lower outlet of the uterus
and is composed primarily of connective
tissue that constitutes the gateway between
the uterus and the vagina.
 Like the rest of the reproductive tract, the
cervix is lined with mucosal cells.
 These cells make significant changes as the
animal goes from one estrous cycle to
another and during gestation or pregnancy.
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN FEMALE MAMMALS? WHAT ARE
THE FUNCTIONS OF THOSE ORGANS?

D. Vagina—The vagina
serves as the female
organ of copulation at
mating and as the birth
canal at parturition.
 It
is the passage
between the cervix and
the vulva.
 The lining is moist
during estrus and dry
when the animal is not
in estrus.
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN FEMALE MAMMALS? WHAT ARE
THE FUNCTIONS OF THOSE ORGANS?

E. Bladder—The bladder collects the liquid
waste, which is called urine.
 The
urine passes
through the urethra to
the vagina.
 The urethra attaches
to the floor of the vagina
between the cervix and
the vulva.
 The bladder is not
considered part of the reproductive tract in
females.
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN FEMALE MAMMALS? WHAT ARE
THE FUNCTIONS OF THOSE ORGANS?

F. Vulva—The vulva is the external opening
of the reproductive and urinary systems.
 The
exterior and visible
part of the vulva consists
of two folds called the
labia majora.
 The labia minora are two
folds located just inside
the labia majora.
WHAT ARE THE MAJOR REPRODUCTIVE
ORGANS IN FEMALE MAMMALS? WHAT ARE
THE FUNCTIONS OF THOSE ORGANS?

G. Clitoris—The clitoris
is the sensory and
erectile organ of the
female.
 It
is located just inside
the vulva.
 The clitoris develops
from the same
embryonic tissue as the
penis in the male and
produces sexual
stimulation during
copulation.
3.8 EXPLAIN ARTIFICIAL INSEMINATION AND
IDENTIFY ITS ADVANTAGES AND
DISADVANTAGES
WHAT ARE THE STEPS INVOLVED
IN ARTIFICIAL INSEMINATION?
Artificial insemination is the placing of
semen in the female reproductive tract by
artificial techniques.
 The use of this technique
has increased over the past
several years due to
advancements in technology.
 The process varies by species, but it
typically involves specialized equipment
and a trained technician.

WHAT ARE THE STEPS INVOLVED
IN ARTIFICIAL INSEMINATION?
The technician deposits a prepared unit of
semen into the reproductive tract of the
female at a predetermined time.
 The objective of artificial insemination is
to deposit the semen at the appropriate
time to achieve fertilization.
 Timing varies by species of animal and
should be closely studied prior to
implementing artificial insemination.

WHAT ARE THE STEPS INVOLVED
IN ARTIFICIAL INSEMINATION?
There are several different segments that
support the process of artificial
insemination.
 Some of the major segments include:
 A. Semen collection—Artificial insemination
requires that semen be collected from the
male.

Semen may be collected
via
manual stimulation or the
use of
an artificial vagina.
 The technique used depends on the species
from which the semen is being collected.

WHAT ARE THE STEPS INVOLVED
IN ARTIFICIAL INSEMINATION?





Manual stimulation involves the use of an electronic
probe to encourage ejaculation.
While this process produces a semen sample, it has
been determined that a more appropriate sample
can be collected if the male is stimulated.
This can be achieved by utilizing an artificial vagina.
It involves allowing the male to mount a dummy
animal and inserting the penis into an artificial
vagina.
This process more closely simulates naturally
breeding, resulting in a higher quality semen sample.
WHAT ARE THE STEPS INVOLVED
IN ARTIFICIAL INSEMINATION?

B. Semen evaluation—After semen is
collected from the male, it
is evaluated for quality.
 Only
the highest quality
semen is utilized for
artificial insemination.
 The semen must be evaluated under a
microscope to verify that it contains an
appropriate number of living sperm cells.
 If approved for use, the sperm is then
processed to increase utilization.
WHAT ARE THE STEPS INVOLVED
IN ARTIFICIAL INSEMINATION?

C. Semen extension—Semen is extended
during the processing phase, which
allows for a single collection to be
divided into many units.
Only one unit is required for
artificial insemination; by extending it, the
semen can be used for several breedings.
 To extend semen, specialized compounds
are added to enhance the viability and
storage of the sperm cells.
 Depending on the species, often nutrients
are added to expand the mass of each
semen unit.

WHAT ARE THE STEPS INVOLVED
IN ARTIFICIAL INSEMINATION?

D. Semen storage—Semen is stored in
one of two ways.
 It
is either frozen to extremely low
temperatures or maintained fresh until use.
 How semen is stored depends on the
species.
 For example, cattle semen is slowly cooled
and frozen at a temperature of –320°F (–
196°C).
 Liquid nitrogen is used to obtain these
extreme temperatures.
WHAT ARE THE STEPS INVOLVED
IN ARTIFICIAL INSEMINATION?
 Properly
frozen and stored semen can remain
viable and be used 30 to 40 years later.
 The frozen semen is thawed prior to use in a
95 to 98°F (33 to 34°C) water bath.
 It is then ready to be deposited in the female.
 Fresh semen cannot be stored for such long
periods of time.
 For
example, collections from pigs are kept at
approximately 60°F (16°C) for two to four days.
 Fresh
semen becomes less fertile over time,
so immediate use improves the chances of
successful insemination.
WHAT ARE THE STEPS INVOLVED
IN ARTIFICIAL INSEMINATION?
3.9 DISCUSS GENETIC ENGINEERING AND ITS
EFFECT ON ANIMAL AGRICULTURE
WHAT IS GENETIC ENGINEERING, AND WHAT
ARE THE STEPS OF RECOMBINANT DNA
TECHNOLOGY?

A. Genetic engineering is a form of biotechnology
in which genetic information is changed to make a
new product.



Through this process, sections of the DNA strand are
cut out, and new sections are inserted.
Gene transfer is the moving of a gene from one
organism to another.
Genetic engineering is a means of complementing
traditional breeding programs.
WHAT IS GENETIC ENGINEERING, AND WHAT
ARE THE STEPS OF RECOMBINANT DNA
TECHNOLOGY?
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B. Recombinant DNA is gene slicing.
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Genes are cut out of a DNA strand with a restriction
enzyme that works like a scalpel.
The genes are then inserted into circular DNA
molecules in bacteria plasmids.
Plasmids are circular pieces of DNA found outside the
nucleus in bacteria.
The plasmid is inserted into the cell that is to be
altered, which allows the DNA of two different
organisms to be combined.
Recombinant DNA is a very complicated and complex
procedure.
Most cells die in the process.
Many surviving cells do not have the new DNA present
in the nucleus.
REVIEW
3.1 Define Terms
 3.2 Discuss Mendel’s contributions to the study
of genetics
 3.3 Identify the parts of and explain the
functions of cells, chromosomes, and genes
 3.4 Differentiate between genotype and
phenotype
 3.5 Compare purebred breeding and
crossbreeding
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REVIEW
3.6 Identify factors to consider in selecting
breeding animals
 3.7 Describe reproduction processes in
agricultural animals
 3.8 Explain artificial insemination and identify
its advantages and disadvantages
 3.9 Discuss genetic engineering and its effect
on animal agriculture
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