This document discusses human genetics and inheritance. It begins by describing human chromosomes, including that humans have 46 total chromosomes, with two sex chromosomes (XX for females and XY for males) that determine sex. The rest are autosomal chromosomes. It then discusses several examples of human genetic traits, including blood type, which is determined by genes on certain chromosomes. Specific genetic disorders like sickle cell anemia and cystic fibrosis are caused by mutations in single genes. The document also covers sex-linked traits, which are inherited differently since they are located on the X or Y chromosome.
Heredity is the passing on of characteristics from one generation to the next. It is the reason why offspring look like their parents. It also explains why cats always give birth to kittens and never puppies. The process of heredity occurs among all living things including animals, plants, bacteria, protists and fungi. The study of heredity is called genetics and scientists that study heredity are called geneticists.
Through heredity, living things inherit traits from their parents. Traits are physical characteristics. You resemble your parents because you inherited your hair and skin color, nose shape, height, and other traits from them.
Cells are the basic unit of structure and function of all living things. Tiny biochemical structures inside each cell called genes carry traits from one generation to the next. Genes are made of a chemical called DNA (deoxyribonucleic acid). Genes are strung together to form long chains of DNA in structures known as chromosomes. Genes are like blueprints for building a house, except that they carry the plans for building cells, tissues, organs, and bodies. They have the instructions for making the thousands of chemical building blocks in the body. These building blocks are called proteins. Proteins are made of smaller units called amino acids. Differences in genes cause the building of different amino acids and proteins. These differences cause individuals to have different traits such as hair color or blood types.
A gene gives only the potential for the development of a trait. How this potential is achieved depends partly on the interaction of the gene with other genes. But it also depends partly on the environment. For example, a person may have a genetic tendency toward being overweight. But the person's actual weight will depend on such environmental factors as how what kinds of food the person eats and how much exercise that person does.
The slide include contents:
Mutation-Definition
Levels of Mutation
Features of Mutation
Types of Mutation
Mutations based on functional effects of the change
Genetic disorders
Heredity is the passing on of characteristics from one generation to the next. It is the reason why offspring look like their parents. It also explains why cats always give birth to kittens and never puppies. The process of heredity occurs among all living things including animals, plants, bacteria, protists and fungi. The study of heredity is called genetics and scientists that study heredity are called geneticists.
Through heredity, living things inherit traits from their parents. Traits are physical characteristics. You resemble your parents because you inherited your hair and skin color, nose shape, height, and other traits from them.
Cells are the basic unit of structure and function of all living things. Tiny biochemical structures inside each cell called genes carry traits from one generation to the next. Genes are made of a chemical called DNA (deoxyribonucleic acid). Genes are strung together to form long chains of DNA in structures known as chromosomes. Genes are like blueprints for building a house, except that they carry the plans for building cells, tissues, organs, and bodies. They have the instructions for making the thousands of chemical building blocks in the body. These building blocks are called proteins. Proteins are made of smaller units called amino acids. Differences in genes cause the building of different amino acids and proteins. These differences cause individuals to have different traits such as hair color or blood types.
A gene gives only the potential for the development of a trait. How this potential is achieved depends partly on the interaction of the gene with other genes. But it also depends partly on the environment. For example, a person may have a genetic tendency toward being overweight. But the person's actual weight will depend on such environmental factors as how what kinds of food the person eats and how much exercise that person does.
The slide include contents:
Mutation-Definition
Levels of Mutation
Features of Mutation
Types of Mutation
Mutations based on functional effects of the change
Genetic disorders
This topic raises some engaging issues of debate concerning the moral justification for exploiting
species and the moral imperative for conserving them. Do other organisms have a right to moral
consideration? How is this justified? Do panda bears have a greater right than lichens? What about the rights
of “pest” or pathogenic organisms? To what extent are these a
Sex-determination and Sex-linked Inheritance.pptxSeemaGaikwad15
The sexually reproducing organisms are classified into two types such as monoecious (hermaphrodite) and dioecious. In monoecious organisms, both male and female gametes (sex cells) are produced by a single individual. The organisms in which both male and female gametes are produced by different individuals are called dioecious. Living organisms, with a very few exceptions, are differentiated into male and female individuals. The sexes of the individuals are genetically determined.
The biological system that determines the development of sexual characteristics in an organism is called sex determination.
There are two different systems of sex determination- Chromosomal sex determination and Non-genetic sex determination.
Breaking down Biology into simpler bits is the most effective way to learn hence this presentation aims to simplify the concept of 'Linked Inheritance' which makes understanding Inheritance better.
B4FA 2012 Nigeria: Principles of Genetics - Charles Amadib4fa
Presentation by Dr Charles Amadi, National Root Crops Research Centre, Umudike, Nigeria
Delivered at the B4FA Media Dialogue Workshop, Ibadan, Nigeria - September 2012
www.b4fa.org
Safalta Digital marketing institute in Noida, provide complete applications that encompass a huge range of virtual advertising and marketing additives, which includes search engine optimization, virtual communication advertising, pay-per-click on marketing, content material advertising, internet analytics, and greater. These university courses are designed for students who possess a comprehensive understanding of virtual marketing strategies and attributes.Safalta Digital Marketing Institute in Noida is a first choice for young individuals or students who are looking to start their careers in the field of digital advertising. The institute gives specialized courses designed and certification.
for beginners, providing thorough training in areas such as SEO, digital communication marketing, and PPC training in Noida. After finishing the program, students receive the certifications recognised by top different universitie, setting a strong foundation for a successful career in digital marketing.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
3. Human Chromosomes
Cell biologists analyze chromosomes by
looking at karyotypes.
Cells are photographed during mitosis.
Scientists
then cut out the
chromosomes
from the
photographs
and group them
together in
pairs.
Copyright Pearson Prentice Hall
4. A picture of an individual’s
chromosomes, arranged in
homologous pairs, is called a
karyotype.
Copyright Pearson Prentice Hall
Human
Karyotype
5. Human Chromosomes
Humans have 46 chromosomes.
Two are called sex chromosomes,
because they determine an
individual's sex.
•Females have two X
chromosomes.
•Males have one X chromosome
and one Y chromosome.
Copyright Pearson Prentice Hall
6. Human Chromosomes
The other 44 chromosomes are
known as autosomal chromosomes,
or autosomes.
Copyright Pearson Prentice Hall
7. Human Chromosomes
All human egg cells carry a
single X chromosome (23,X).
Half of all sperm cells carry an
X chromosome (23,X) and half
carry a Y chromosome (23,Y).
About half of the zygotes will be 46,XX
(female) and half will be 46,XY (male).
Copyright Pearson Prentice Hall
8. Human Chromosomes
Males and
females are
born in a
roughly 50 : 50
ratio because
of the way in
which sex
chromosomes
segregate
during meiosis.
Copyright Pearson Prentice Hall
11. Human Traits
Human Traits
In order to apply Mendelian genetics to
humans, biologists must identify an
inherited trait controlled by a single gene.
They must establish that the trait is
inherited and not the result of
environmental influences.
They have to study how the trait is
passed from one generation to the next.
Copyright Pearson Prentice Hall
12. Human Traits
Pedigree Charts
A pedigree chart shows the
relationships within a family.
Genetic counselors analyze pedigree
charts to infer the genotypes of family
members.
Copyright Pearson Prentice Hall
Active art
13. Human Traits
A circle
represents
a female.
A horizontal line
connecting a male and a
female represents a
marriage.
Copyright Pearson Prentice Hall
A shaded
circle or
square
indicates that a
person
expresses the
trait.
A square
represents
a male.
A vertical line and
a bracket connect
the parents to their
children.
A circle or square that is
not shaded indicates that
a person does not express
the trait.
14. Genes and the Environment
Some obvious human traits are almost
impossible to associate with single genes.
Traits, such as the shape of your
eyes or ears, are polygenic,
meaning they are controlled by
many genes.
Many of your personal traits are only
partly governed by genetics.
Copyright Pearson Prentice Hall
15. Human Genes
The human genome includes tens of
thousands of genes.
In 2003, the DNA sequence of the human
genome was published.
In a few cases, biologists were able to
identify genes that directly control a
single human trait such as blood type.
Copyright Pearson Prentice Hall
16. Blood Group Genes
Human blood comes in a variety of
genetically determined blood groups.
A number of genes are responsible for
human blood groups.
The best known are the ABO blood
groups and the Rh blood groups.
Copyright Pearson Prentice Hall
17. Human Genes
The Rh blood group is determined by a single
gene with two alleles—positive and negative.
The positive (Rh+) allele is
dominant, so individuals who are
Rh+/Rh+ or Rh+/Rh are said to be
Rh-positive.
Individuals with two Rh- alleles are
said to be Rh-negative.
Copyright Pearson Prentice Hall
18. Human Genes
ABO blood group
•There are three alleles for this
gene, IA, IB, and i.
•Alleles IA and IB are codominant.
Copyright Pearson Prentice Hall
19. Human Genes
Individuals with alleles IA and IB
produce both A and B antigens,
making them blood type AB.
Copyright Pearson Prentice Hall
20. Human Genes
The i allele is recessive.
Individuals with alleles IAIA or IAi
produce only the A antigen,
making them blood type A.
Copyright Pearson Prentice Hall
21. Human Genes
Individuals with IBIB or IBi alleles
are type B.
Copyright Pearson Prentice Hall
22. Human Genes
Individuals who are homozygous
for the i allele (ii) produce no
antigen and are said to have
blood type O.
Copyright Pearson Prentice Hall
24. Recessive Alleles
The presence of a normal, functioning
gene is revealed only when an abnormal
or nonfunctioning allele affects the
phenotype.
Many disorders are caused by
autosomal recessive alleles.
Copyright Pearson Prentice Hall
26. Dominant Alleles
The effects of a dominant allele
are expressed even when the
recessive allele is present.
Two examples of genetic disorders
caused by autosomal dominant alleles
are achondroplasia and Huntington
disease.
Copyright Pearson Prentice Hall
28. Codominant Alleles
Sickle cell disease is a serious
disorder caused by a
codominant allele.
Sickle cell is found in about 1 out of 500
African Americans.
Copyright Pearson Prentice Hall
30. Sickle Cell Disease is
characterized by the
bent and twisted
shape of the red
blood cells.
Copyright Pearson Prentice Hall
31. Hemoglobin is the protein in red blood
cells that carries oxygen.
In the sickle cell allele, just one DNA base
is changed.
As a result, the abnormal hemoglobin is
less soluble than normal hemoglobin.
Low oxygen levels cause some red blood
cells to become sickle shaped.
Copyright Pearson Prentice Hall
32. There are three phenotypes associated
with the sickle cell gene.
Homozygous dominant- normal
Heterozygous dominant- healthy
with malaria resistance
Homozygous recessive- sickle cell
Sickle cell alleles are
considered codominant.
Copyright Pearson Prentice Hall
33. Malaria and the Sickle Cell Allele
Regions where malaria is
common
Regions where the sickle
cell allele is common
Because the sickle cell allele gives
resistance to malaria it persists in
areas where malaria is a problem.
Copyright Pearson Prentice Hall
34. In both cystic fibrosis and sickle
cell disease, a small change in the
DNA of a single gene affects the
structure of a protein, causing a
serious genetic disorder.
Copyright Pearson Prentice Hall
35. From Gene to Molecule
Cystic Fibrosis
Cystic fibrosis is caused by a
recessive allele.
Sufferers of cystic fibrosis produce a
thick, heavy mucus that clogs their lungs
and breathing passageways.
Copyright Pearson Prentice Hall
36. The most
common allele
that causes
cystic fibrosis is
missing 3 DNA
bases.
As a result, the
amino acid
phenylalanine is
missing from the
CFTR protein.
Copyright Pearson Prentice Hall
37. From Gene to Molecule
Normal CFTR is a
chloride ion
channel in cell
membranes.
Abnormal CFTR
cannot be
transported to the
cell membrane.
Copyright Pearson Prentice Hall
38. The cells in the
person’s airways
are unable to
transport chloride
ions.
As a result, the
airways become
clogged with a
thick mucus.
Copyright Pearson Prentice Hall
39. These diseases are autosomal
recessive because you only need
one functional gene to make a good
protein.
FF Ff ff
Copyright Pearson Prentice Hall
Makes
good
protein
Makes some
good protein
and some that
doesn’t work
Makes protein
that doesn’t
work
41. Sex-Linked Genes
•The X chromosome and the Y
chromosomes determine sex.
•Genes located on sex
chromosomes are called sex-linked
genes.
•More than 100 sex-linked genetic
disorders have now been mapped to the
X chromosome.
Copyright Pearson Prentice Hall
42. Sex-Linked Genes
The Y
chromosome is
much smaller
than the X
chromosome
and appears to
contain only a
few genes.
X Chromosome
Copyright Pearson Prentice Hall
Duchenne muscular
dystrophy
Melanoma
X-inactivation center
X-linked severe combined
immunodeficiency (SCID)
Colorblindness
Hemophilia
Y Chromosome
Testis-determining
factor
43. For a recessive allele to be expressed in
females, there must be two copies of the
allele, one on each of the two X
chromosomes.
Males have just one X
chromosome. Thus, all X-linked
alleles are expressed in
males, even if they are
recessive.
Copyright Pearson Prentice Hall
44. Colorblindness
Three human genes associated with color
vision are located on the X chromosome.
In males, a
defective version
of any one of
these genes
produces
colorblindness.
Copyright Pearson Prentice Hall
46. Hemophilia
•The X chromosome also carries genes
that help control blood clotting. A
recessive allele in either of these two
genes may produce hemophilia.
• In hemophilia, a protein necessary for
normal blood clotting is missing.
•Hemophiliacs can bleed to death from
cuts and may suffer internal bleeding if
bruised.
Copyright Pearson Prentice Hall
47. Duchenne Muscular Dystrophy
•Duchenne muscular dystrophy is a sex-linked
disorder that results in the
weakening and loss of skeletal muscle.
• It is caused by a defective version of the
gene that codes for a muscle protein.
Copyright Pearson Prentice Hall
48. Recessive traits from genes
on the X-chromosome, like
color blindness and
hemophilia,
are much
more
common
in males.
49. X-Chromosome Inactivation
•British geneticist Mary Lyon discovered that
in female cells, one X chromosome is
randomly switched off.
•The inactive X chromosome forms a
dense region in the nucleus known as
a Barr body.
• Barr bodies are generally
not found in males because
their single X chromosome
is still active.
Copyright Pearson Prentice Hall
50. GENETIC DISORDERS caused by
NON-DISJUNCTION
•The most common error in meiosis
occurs when homologous
chromosomes fail to separate.
Copyright Pearson Prentice Hall
52. GENETIC DISORDERS caused by
NON-DISJUNCTION
•This is known as nondisjunction,
which means, “not coming apart.”
•nondisjunction causes abnormal
numbers of chromosomes
Copyright Pearson Prentice Hall
53.
54. Down Syndrome
•If two copies of an autosomal
chromosome fail to separate
during meiosis, an individual
may be born with three copies
of a chromosome.
•Down syndrome involves three
copies of chromosome 21.
Copyright Pearson Prentice Hall
55. Chromosomal Disorders
Down syndrome
produces mild to
severe mental
retardation.
It is characterized by:
• increased
susceptibility to
many diseases
•higher frequency
of some birth
defects
Down Syndrome Karyotype
Copyright Pearson Prentice Hall
56. Sex Chromosome Disorders
• In females, nondisjunction can lead
to Turner’s syndrome.
•A female with Turner’s syndrome
usually inherits only one X
chromosome (karyotype 45,X).
•Women with Turner’s syndrome are
sterile.
Copyright Pearson Prentice Hall
57. Chromosomal Disorders
In males, nondisjunction causes
Klinefelter’s syndrome (karyotype 47,XXY).
The extra X chromosome interferes with
meiosis and usually prevents these
individuals from reproducing.
Copyright Pearson Prentice Hall
59. 14–3 Human Molecular Genetics 14-3 Human Molecular Genetics
Copyright Pearson Prentice Hall
60. Human DNA Analysis
• There are roughly 6 billion base pairs in
your DNA.
•Biologists search the human genome
using sequences of DNA bases.
Copyright Pearson Prentice Hall
61. Genetic tests are available for hundreds of
disorders.
DNA testing can pinpoint the exact
genetic basis of a disorder.
Copyright Pearson Prentice Hall
62. •DNA fingerprinting analyzes the
DNA repeats which make a unique
pattern for each individual.
•Only identical twins are genetically
identical.
•DNA samples can be obtained from blood,
sperm, and hair strands with tissue at the
base.
Copyright Pearson Prentice Hall
63. Human DNA Analysis
Chromosomes
contain large
amounts of
DNA called
repeats that do
not code for
proteins.
This DNA pattern
varies from person
to person.
Copyright Pearson Prentice Hall
Active art
64. Restriction enzymes are used to cut the
DNA into fragments containing genes and
repeats.
Copyright Pearson Prentice Hall
65. DNA fragments
are separated
using gel
electrophoresis.
Fragments
containing repeats
are labeled.
This produces a
series of bands—
the DNA
fingerprint.
Copyright Pearson Prentice Hall
67. In 1990, scientists in the United States
and other countries began the Human
Genome Project.
The Human Genome Project is
an ongoing effort to analyze the
human DNA sequence.
In June 2000, a working copy of the
human genome was essentially
complete.
Copyright Pearson Prentice Hall
68. Research groups are analyzing the DNA
sequence, looking for genes that may
provide clues to the basic properties of life.
Biotechnology companies are looking for
information that may help develop new
drugs and treatments for diseases.
Copyright Pearson Prentice Hall
69. A Breakthrough for Everyone
•Data from publicly supported research
on the human genome have been
posted on the Internet on a daily basis.
•You can read and analyze the latest
genome data.
Copyright Pearson Prentice Hall
70. In gene therapy, an absent or
faulty gene is replaced by a
normal, working gene.
The body can then make the correct
protein or enzyme, eliminating the cause
of the disorder.
Copyright Pearson Prentice Hall
71. Viruses are often
used because of
their ability to enter
a cell’s DNA.
Virus particles are
modified so that they
cannot cause
disease.
Normal hemoglobin gene
Genetically engineered virus
Copyright Pearson Prentice Hall
72. A DNA fragment containing a replacement
gene is spliced to viral DNA.
Bone marrow cell
Copyright Pearson Prentice Hall
Chromosomes
Nucleus
Genetically engineered virus
73. The patient is then infected with the
modified virus particles, which should
carry the gene into cells to correct genetic
defects.
Copyright Pearson Prentice Hall
74. Copyright Pearson Prentice Hall
14–1
A chromosome that is not a sex chromosome is
know as a(an)
a. autosome.
b. karyotype.
c. pedigree.
d. chromatid.
75. Copyright Pearson Prentice Hall
14–1
Whether a human will be a male or a female is
determined by which
a. sex chromosome is in the egg cell.
b. autosomes are in the egg cell.
c. sex chromosome is in the sperm cell.
d. autosomes are in the sperm cell.
76. Copyright Pearson Prentice Hall
14–1
Mendelian inheritance in humans is typically
studied by
a. making inferences from family
pedigrees.
b. carrying out carefully controlled
crosses.
c. observing the phenotypes of individual
humans.
d. observing inheritance patterns in other
animals.
77. Copyright Pearson Prentice Hall
14–1
An individual with a blood type phenotype of O
can receive blood from an individual with the
phenotype
a. O.
b. A.
c. AB.
d. B.
78. Copyright Pearson Prentice Hall
14–1
The ABO blood group is made up of
a. two alleles.
b. three alleles.
c. identical alleles.
d. dominant alleles.
79. Copyright Pearson Prentice Hall
14–2
The average human gene consists of how many
base pairs of DNA?
a. 3000
b. 300
c. 20
d. 30,000
80. Copyright Pearson Prentice Hall
14–2
Which of the following genotypes indicates an
individual who is a carrier for colorblindness?
a. XCX
b. XCXc
c. XcY
d. XCY
81. Copyright Pearson Prentice Hall
14–2
Colorblindness is much more common in males
than in females because
a. the recessive gene on the male’s single X
chromosome is expressed.
b. genes on the Y chromosome make genes on
the X chromosome more active.
c. females cannot be colorblind.
d. colorblindness is dominant in males and
recessive in females.
82. Copyright Pearson Prentice Hall
14–2
The presence of a dense region in the nucleus
of a cell can be used to determine the
a. sex of an individual.
b. blood type of an individual.
c. chromosome number of an individual.
d. genotype of an individual.
83. Copyright Pearson Prentice Hall
14–2
Nondisjunction occurs during
a. meiosis I.
b. mitosis.
c. meiosis II.
d. between meiosis I and II.
84. Copyright Pearson Prentice Hall
14–3
DNA fingerprinting analyzes sections of DNA
that have
a. Little or no known function but are identical
from one individual to another.
b. little or no known function but vary widely
from one individual to another.
c. a function and are identical from one
individual to another.
85. Copyright Pearson Prentice Hall
14–3
DNA fingerprinting uses the technique of
a. gene therapy.
b. allele analysis.
c. gel electrophoresis.
d. gene recombination.
86. Copyright Pearson Prentice Hall
14–3
Repeats are areas of DNA that
a. do not code for proteins.
b. code for proteins.
c. are identical from person to person.
d. cause genetic disorders.
87. Copyright Pearson Prentice Hall
14–3
Data from the human genome project is
available
a. only to those who have sequenced the
DNA.
b. to scientists who are able to understand the
data.
c. by permission to anyone who wishes to do
research.
d. to anyone with Internet access.
88. Copyright Pearson Prentice Hall
14–3
Which statement most accurately describes
gene therapy?
a. It repairs the defective gene in all cells of the
body.
b. It destroys the defective gene in cells where
it exists.
c. It replaces absent or defective genes with a
normal gene.
d. It promotes DNA repair through the use of
enzymes.