Subject: Advanced Nursing Practice
Mr. Gopal singh
MSc(N) Child Health Nursing MSc(N) 1st year
SGL Nursing College
SGL Nursing College
At the end of teaching students will be able to:
Enlist the type of cell division.
Define human genome project.
Disadvantages of human genome project.
MEANING OF TERM GENETICS
The term genetics was introduced by Bateson in 1906.
It was derived from Greek word ‘gene’ which means ‘to
become’ or ‘to grow into’. Therefore, genetics is the
science of coming into being.
Genetics is the branch of biological science
which deals with the transmission of characteristics from
parents to offspring.
A gene is the basic physical and functional unit
of hereditary. Genes, which are made up of DNA,
act as RNA instructor to make molecules called
In humans genes vary in size from a few hundred
DNA bases to more than 2 million bases. The
Human Genome Project has estimated that
humans have between 20,000-25,000 genes.
Every person has two copies of each gene, one
inherited from each parent.
In the nucleus of each cell, the DNA molecule is
packed into thread like structure called
Each chromosome is made up of DNA tightly coiled
many times around proteins called histones that
support its structure.
Chromosomes are not visible in the cell’s nucleus not
even under a microscope when the cell is not
However, the DNA that makes up chromosomes
becomes more tightly packed during cell division
and is then visible under a microscope.
DEOXYRIBONUCLEIC ACID (DNA)
It is a nucleic acid that contains the genetic
instructions for the development and function of
living things. All known cellular life and some
viruses contain DNA.
The main role of DNA in the cell is the long-term
storage of information. It is often compared to a
blueprint, since it contains the instructions to
construct other components of the cell, such as
proteins and RNA molecules.
The DNA segments that carry genetic information
are called gene, but other DNA sequences have
structural purposes, or are involved in regulating the
expression of genetic information.
This is a continuous process involving four
distinct stages seen by light microscopy.
Meiosis produces gametes. On fertilization
when the male gamete(sperm cells) and the female
gamete(ovum) unite, the resulting zygote is diploid,
because each gamete was haploid.
Unlike mitosis, meiosis involve two distinct
cell division rather than one. Additionally meiosis
produce four daughter cells not two, all different
from the parent cell from each other.
This is the basis of genetic diversity and the
uniqueness of each human individual.
1. FIRST MEIOTIC DIVISION
2. SECOND DIVISION DIVISION
The term mutation is defined as a physic-chemical
change in the gene, large or small. The gene
is permanent change in DNA base
sequence that makes up a gene. Mutation range
in size from a single DNA building block to a large
segment of a chromosome.
Gene mutations occur in two ways:
Inherited from a parent, or
Acquired during a person’s lifetime.
EFFECT OF GENE MUTATION ON
HEALTH AND DEVELOPMENT:
To function correctly, each cell depends on
thousands of proteins to do their jobs in the right
places at the right times.
Something, gene mutation prevents one more
of these proteins from working properly.
By changing a gene’s instructions for making a
protein to protein, a mutation can cause the
protein to malfunction or to be missing entirely.
When it can disrupt normal
development or cause a medical condition. A condition
caused by mutations in one or more genes is called a
MECHANISM OF INHERITANCE
A particular disorder might be described as
“running in a family” if more than one person in the
family has the condition.
Some disorders that affect multiple family members
are caused by gene mutations, which can be
inherited. Other conditions that appear to run in
families are not inherited.
Instead, environmental factors such as dietary habits
or a combination of genetic and environmental
factors are responsible for these disorders.
MENDELLAN THEORY OF INHERITANCE
Mendelian Inheritance is so called because our
understanding of it started with the observations
of an Augustinian monk named Gregor Mendel in
the 19th century.
Genes provide the information for the growth,
development and function of our bodies. When a
gene is changed, there is a different massage sent
to the cells. A gene change that makes the genes
faulty is called a mutation.
PATTERN OF INHERITANCE
One mutated copy of the gene in each cell is
sufficient for a person to be affected by an
autosomal dominant disorder.
Each affected person usually has one
affected parent. Autosomal dominant disorders
tend to occur in every generation of an affected
MAIN CHARACTERISTICS OF
AUTOSOMAL DOMINANT INHERITANCE
Vertical transmission, men and women equally
affected, variable expression, reduced penetrance
(in some disorder), and advanced paternal age
associated with sporadic cases. Examples of
autosomal dominant disorder:
Neurofibromatosis type 1
Hereditary breast and ovarian cancer
Two mutated copies of the gene are present in
each cell when a person has an autosomal
recessive disorder. An affected person usually has
unaffected parents who each carry a single copy
of the mutated gene.
Autosomal recessive disorders are typically not
seen in every generation of
an affected family.
MAIN FEATURES OF AUTOSOMAL
Horizontal occurrence in families, men and
equally, associated with
consanguinity and association with particular
Examples of autosomal recessive disorders:
Sickle cell anaemia
SEX LINKED INHERITANCE
a.) X- linked Dominant(affected father)
X-linked dominant disorders are caused
by mutations in genes on the X chromosomes .
Females are more frequently affected than males
and the chance of passing on an X-linked
dominant disorder differs between men and
B.) X-LINKED RECESSIVE
X-linked recessive disorders are also caused by
mutations in genes on the X chromosome.
Males are more frequently affected than
females and the chance of passing on the disorder
differs between men and women.
X-LINKED RECESSIVE(AFFECTED FATHER)
In this example a man with an X-linked recessive
condition has two unaffected daughters who each
carry one copy of the gene mutation and two
unaffected sons who do not have the mutation.
X-LINKED RECESSIVE (CARRIER
In this example an unaffected woman carrier one
copy of a gene mutation for an X-linked recessive
disorder. She has an affected son, an unaffected
daughter who carries one copy of the mutation
and two unaffected children who do not have the
HUMAN GENOME PROJECT
The genome is defined as the total genetic
material contained within the chromosomes of an organism and
carried by DNA. Transcriptome is the transcribed messenger
RNA complement and the proteome the translated protein
The Human Genome Project (HGP) began formally
in 1990 and is a 13year effort coordinated by the US
Department of Energy and the National institute of Health
(NIH). It finalized almost 2years earlier than expected. It was
an enormous task as the aim was to sequence 3 billion base
pairs and identified approximately 30,000 genes.
MAJOR WORK DONE UNDER HGP
1. Isolation of disease genes
a.) Functional cloning
b.) Positional cloning
2. Comparative biology of humans and other
3. Advances in molecular diagnostic
4. Therapeutical benefits
OUTCOME OF HGP
1. The complete genome sequence is likely to yield
predictable and unpredictable results and benefits. It
will provide the ultimate genetics “blue print” of the
2. The amount of time required to identify genes via
positional cloning and other approaches continue to
3. One of the unanticipated outcomes understanding of
environmental as well as genetic factors in
development and diseases.
4. Cloning of diseases gene helps in diagnosis of
various genetics factor in development and diseases.
5. Helps in development of Pharmacogenomics.
5. Has a genetic basis in identifying various
6. Helps in understanding of complex social trait.
7. Helps in improved knowledge on mutations.
8. Better understanding of developmental biology.
9. Improvement in gene therapy.
10. Understanding of polygenic disorders. E.g.
11. Identification of human gene and their functions.
1. The research on human will make very sensitive
data available that will affect the personal and
private lines of individual.
2. Once it is known that a person carries genes for
an incurable disease, the parson can go in
depression by thinking how the society will treat
3. Individuals’ substandard genome sequence may
Scientifical American The study reported that 150 genetic
variations that could be used to predict
whether a person was genetically
included to see their 100th birthday. The
results were based on research through
the genomes of more than 1,000
entrains. Previous studies have
suggested that tiny contributions from
hundred of genetic factors combine to
account for about 25% of variation in
human longevity. The remaining 75% is
attributed to environmental influence.
Maynard V. Olson
Page no. 1-27.
The central preoccupation of human
genetics is an effort to understand the
genotypic basis of human phenotypic
diversity. Although recent progress in
identifying the gene that when mutated,
underline major genetic influences on the
vast range of variables and at least partially
1. Versha Katira, Basics of human genetics,
Published by CBS Publishers, Edition 1st Page no.
2. Daniel l. Hartl, Elizabeth W. Jones, Essential
genetics a genomics prospective. Published by
Jones and Bartlett. Edition 3rd Page no. 250-251.
3. Navneet Kumari, Essential genetics, published by
Lotus publisher, Edition 1st Page no.10-37.
4. Suresh Kumar Sharma, Human Genetics in
nursing, Published by Jaypee publisher. Edition 1st.
Page no. 1-45.