MTCY21-18: CYTOGENETICS
MODULE 1: GENETICS
1ST SEMESTER I S.Y 2021 – 2022
LECTURER: MS. MA. TERESA MARCELO
DEFINITION OF GENETICS MENDEL’S WORK ON TRANSMISSION OF
TRAITS
“Genetics is a field of science that includes the study of
inheritance and genetic variations by investigating the Johann Mendel was born in 1822 to a peasant family in
DNA, genes, genome, chromosome and other the Central European village of Heinzendorf. An excellent
components of it.” student in high school, he studied philosophy for several
years afterward and in 1843, taking the name Gregor, was
The term “Genetics” was coined by William Bateson is
admitted to the Augustinian Monastery of St. Thomas in
1905.
Brno, now part of the Czech Republic. In 1849, he was
It is a Greek word from “genetikos” (generative) relieved of pastoral duties, and from 1851 to 1853, he
and “genesis” (origin). attended the University of Vienna, where he studied
physics and botany. He returned to Brno in 1854, where
he taught physics and natural science for the next 16
years. Mendel received support from the monastery for
HISTORY OF GENETICS his studies and research throughout his life.
It started with Augustinian friar Gregor In 1856, Mendel performed his first set of hybridization
Johann Mendel’s work on pea plants, published in 1866, experiments with the garden pea, launching the research
described what came to be known as Mendelian phase of his career. His experiments continued until 1868,
Inheritance. when he was elected abbot of the monastery. Mendel first
reported the results of some simple genetic crosses
1900 marked the "rediscovery of Mendel" by Hugo de between certain strains of the garden pea in 1865.
Vries, Carl Correns and Erich von Tschermak, and by Although his findings went unappreciated until the turn
1915 the basic principles of Mendelian genetics had been of the century, well after his death, his work was not the
applied to a wide variety of organisms—most notably the first attempt to provide experimental evidence pertaining
fruit fly Drosophila melanogaster. Led by Thomas Hunt to inheritance. Mendel’s success where others had failed
Morgan and his fellow "drosophilists", geneticists can be attributed, at least in part, to his elegant
developed the Mendelian model, which was widely experimental design and analysis. In 1884, Mendel died
accepted by 1925. of a kidney disorder.
In the 1940s and early 1950s, experiments pointed to Mendel showed remarkable insight into the methodology
DNA as the portion of chromosomes (and perhaps other necessary for good experimental biology. He applied
nucleoproteins) that held genes. quantitative data analysis to his results and showed that
traits are passed from parents to offspring in predictable
A focus on new model organisms such as viruses and
ways. First, he chose an organism that was easy to grow
bacteria, along with the discovery of the double helical
and to hybridize artificially. The pea plant is self-fertilizing
structure of DNA in 1953, marked the transition to the era
in nature, but it is easy to cross-breed experimentally. It
of molecular genetics.
reproduces well and grows to maturity in a single season.
In the following years, chemists developed techniques for Mendel followed seven visible features (we refer to them
sequencing both nucleic acids and proteins, while others as characters, or characteristics), each represented by
worked out the relationship between the two forms of two contrasting forms, or traits. For the character stem
biological molecules: the genetic code. height, for example, he experimented with the
traits tall and dwarf. He selected six other contrasting
The regulation of gene expression became a central issue pairs of traits involving seed shape and color, pod shape
in the 1960s; by the 1970s gene expression could be and color, and flower color and position. From local seed
controlled and manipulated through genetic engineering. merchants, Mendel obtained true-breeding strains, those
In the last decades of the 20th century, many biologists in which each trait appeared unchanged generation after
focused on large-scale genetics projects, sequencing generation in self-fertilizing plants. Mendel’s findings
entire genomes. explained the transmission of traits in pea plants and all
,other higher organisms. His work forms the foundation of
genetics.
CYTOGENETICS
Cytogenetics is a sub-branch of genetics including the
study of inheritance through chromosomal analysis
SOME OF THE MILESTONE DISCOVERIES IN
utilizing techniques such karyotyping, chromosomal
THE GENETICS ARE:
staining and chromosomal banding, and FISH. Structural
and numerical chromosomal abnormalities can be
1842: Wilhelm von Nageli, a Swiss botanist, observed
screened using cytogenetic techniques.
the plant cell.
1866: Mendel’s research work published under the title of
“experiments on plant hybridization.” HUMAN GENETICS
1869: Friedrich Miescher discovered the nucleic acid. The branch of genetics comprises the study of genetic
alteration and its role in the development of the disease
1888: Waldeyer identified the chromosome present in the
especially in humans.
cell.
1889: Richard Altmann purified DNA from the protein.
PREIMPLANTATION GENETICS
1905: William Bateson coined the term “genetics”.
This is the study of characterizing or profiling the genetic
1908: discovery of Hardy-Weinberg’s law.
composition of the embryo before implantation. The
1910: Morgan T, explained that the genes are located on major application of preimplantation genetic is to screen
the chromosomes. Also, they experimented on the high-risk pregnancy. A couple having the previous
Drosophila Melanogaster and determined the nature of history of any genetic disorder can be suggested for
sex-linked traits. preimplantation genetics.
1923: Griffith F, experimented on bacteria and
postulated that the DNA is the genetic material.
CLINICAL GENETICS
1953: Watson and Crick identified the structure of DNA.
This genetic field is involved with the study of disease,
finding the root of the disease, its adverse, related effects,
and its inheritance pattern.
BRANCHES OF GENETICS
PLANT GENETICS
The branch of genetics that deals with the study of genetic
variation and chromosomal abnormalities in plants. The
mechanism of inheritance was developed from
experimenting with plants. The foundation of genetics laid
by experimenting on pea plant by father of genetics,
Mendel.
MICROBIAL GENETICS
Microbial genetics is an applied branch of genetics that
includes the study of the genes, genotypes ad gene
expression of microorganism for various genetic
engineering applications.
MOLECULAR GENETICS
Molecular genetics is an interdisciplinary sub-branch of
genetics dealing with the study of the structure and POPULATION GENETICS
function of DNA as well as genes (at a molecular level) An interdisciplinary branch of genetics that includes the
using techniques such as Polymerase chain reaction and study of genetic difference within and between the
DNA sequencing. population or individual.
,EPIGENETICS Separation is a process of extracting molecules like DNA
or mRNA from other cell debris. After that DNA is purified
The branch of genetics that deals with the study of using the ready to use-kit or using alcohol. Once the
alterations in an organism caused by gene expression purified – good quantity DNA is obtained, it is further
rather than alteration caused by a gene mutation. In processed for the downstream applications.
simple words, epigenetics is a study of gene expression.
PCR: The polymerase chain reaction is a process in
PHYSIOLOGICAL GENETICS which we can amplify millions of copies of a DNA segment
Physiological genetics deals with the study of of our interest in vitro. The process is temperature-
physiological characteristics such as sex differentiation dependent, and divided into three steps:
and sex determination, blood group factor and sickle cell
• Denaturation: the double-stranded DNA
anemia like physiological conditions.
denatured into a single-stranded one.
• Annealing: the Sequence-specific DNA primer
BIOCHEMICAL GENETICS binds/anneal to its complementary sequence on
single-stranded DNA.
The branch of the genetics related to studying the
chemistry of DNA, gene, chromosome, RNA and related • Extension: the Taq DNA polymerase amplifies
biomolecules. the DNA using the 3′ end of the primer.
QUANTITATIVE GENETICS
It is actually a branch of the population genetics which
studies the continuously varying phenotypes.
BEHAVIORAL GENETICS
This field of genetics study the behavioral phenotypes of
an organism governed by the genetic factors.
TECHNIQUES (TOOLS) USED IN THE STUDY
OF GENETICS
Using the molecular genetics techniques one can screen
pathogenic mutation, detect SNPs (single nucleotide
DNA CLONING
polymorphism), minor deletion or duplication at the DNA
level. further, gene expression studies are also possible DNA cloning is a traditional method for the synthesis of
using molecular genetic techniques. A state of the art DNA. Using a cloning vector our sequence of interest can
technique, DNA sequencing is powerful enough to find be synthesized by the bacterial artificial
new variations or mutations. Polymerase chain reaction, chromosome. The method is time-consuming and not so
gene cloning, DNA Sequencing and DNA quantification accurate. It includes tedious steps like cell culture and
are some of the techniques used in molecular genetic isolation.
analysis.
Any of the molecular genetic experiment divided into the
4 sub-steps: DNA SEQUENCING:
• Separation of molecule The method of reading the sequence of DNA using a
computational tool is called DNA sequencing. In this
• Purification of molecules method, we can actually analyze any variation or new
mutation in our sequence of interest using the fluoro-
• Processing of molecule labeled dNTPs.
• Detection of molecule
, CONCLUSION
In a broader sense, genetics is a study of genotype, its
related phenotype, and alterations in the genome. Using
genetics tools, nowadays, the diagnosis of inherited
diseases is a common medical practice.
The Human Genome Project was completed in the year
2013. Now we have the entire genomic sequence of
human. We can use this data for the identification of new
mutations and alterations.
Further, genomic data of so many other organisms are
now available which is used for identification and
characterization of different organisms and species.
MODULE 1: GENETICS
1ST SEMESTER I S.Y 2021 – 2022
LECTURER: MS. MA. TERESA MARCELO
DEFINITION OF GENETICS MENDEL’S WORK ON TRANSMISSION OF
TRAITS
“Genetics is a field of science that includes the study of
inheritance and genetic variations by investigating the Johann Mendel was born in 1822 to a peasant family in
DNA, genes, genome, chromosome and other the Central European village of Heinzendorf. An excellent
components of it.” student in high school, he studied philosophy for several
years afterward and in 1843, taking the name Gregor, was
The term “Genetics” was coined by William Bateson is
admitted to the Augustinian Monastery of St. Thomas in
1905.
Brno, now part of the Czech Republic. In 1849, he was
It is a Greek word from “genetikos” (generative) relieved of pastoral duties, and from 1851 to 1853, he
and “genesis” (origin). attended the University of Vienna, where he studied
physics and botany. He returned to Brno in 1854, where
he taught physics and natural science for the next 16
years. Mendel received support from the monastery for
HISTORY OF GENETICS his studies and research throughout his life.
It started with Augustinian friar Gregor In 1856, Mendel performed his first set of hybridization
Johann Mendel’s work on pea plants, published in 1866, experiments with the garden pea, launching the research
described what came to be known as Mendelian phase of his career. His experiments continued until 1868,
Inheritance. when he was elected abbot of the monastery. Mendel first
reported the results of some simple genetic crosses
1900 marked the "rediscovery of Mendel" by Hugo de between certain strains of the garden pea in 1865.
Vries, Carl Correns and Erich von Tschermak, and by Although his findings went unappreciated until the turn
1915 the basic principles of Mendelian genetics had been of the century, well after his death, his work was not the
applied to a wide variety of organisms—most notably the first attempt to provide experimental evidence pertaining
fruit fly Drosophila melanogaster. Led by Thomas Hunt to inheritance. Mendel’s success where others had failed
Morgan and his fellow "drosophilists", geneticists can be attributed, at least in part, to his elegant
developed the Mendelian model, which was widely experimental design and analysis. In 1884, Mendel died
accepted by 1925. of a kidney disorder.
In the 1940s and early 1950s, experiments pointed to Mendel showed remarkable insight into the methodology
DNA as the portion of chromosomes (and perhaps other necessary for good experimental biology. He applied
nucleoproteins) that held genes. quantitative data analysis to his results and showed that
traits are passed from parents to offspring in predictable
A focus on new model organisms such as viruses and
ways. First, he chose an organism that was easy to grow
bacteria, along with the discovery of the double helical
and to hybridize artificially. The pea plant is self-fertilizing
structure of DNA in 1953, marked the transition to the era
in nature, but it is easy to cross-breed experimentally. It
of molecular genetics.
reproduces well and grows to maturity in a single season.
In the following years, chemists developed techniques for Mendel followed seven visible features (we refer to them
sequencing both nucleic acids and proteins, while others as characters, or characteristics), each represented by
worked out the relationship between the two forms of two contrasting forms, or traits. For the character stem
biological molecules: the genetic code. height, for example, he experimented with the
traits tall and dwarf. He selected six other contrasting
The regulation of gene expression became a central issue pairs of traits involving seed shape and color, pod shape
in the 1960s; by the 1970s gene expression could be and color, and flower color and position. From local seed
controlled and manipulated through genetic engineering. merchants, Mendel obtained true-breeding strains, those
In the last decades of the 20th century, many biologists in which each trait appeared unchanged generation after
focused on large-scale genetics projects, sequencing generation in self-fertilizing plants. Mendel’s findings
entire genomes. explained the transmission of traits in pea plants and all
,other higher organisms. His work forms the foundation of
genetics.
CYTOGENETICS
Cytogenetics is a sub-branch of genetics including the
study of inheritance through chromosomal analysis
SOME OF THE MILESTONE DISCOVERIES IN
utilizing techniques such karyotyping, chromosomal
THE GENETICS ARE:
staining and chromosomal banding, and FISH. Structural
and numerical chromosomal abnormalities can be
1842: Wilhelm von Nageli, a Swiss botanist, observed
screened using cytogenetic techniques.
the plant cell.
1866: Mendel’s research work published under the title of
“experiments on plant hybridization.” HUMAN GENETICS
1869: Friedrich Miescher discovered the nucleic acid. The branch of genetics comprises the study of genetic
alteration and its role in the development of the disease
1888: Waldeyer identified the chromosome present in the
especially in humans.
cell.
1889: Richard Altmann purified DNA from the protein.
PREIMPLANTATION GENETICS
1905: William Bateson coined the term “genetics”.
This is the study of characterizing or profiling the genetic
1908: discovery of Hardy-Weinberg’s law.
composition of the embryo before implantation. The
1910: Morgan T, explained that the genes are located on major application of preimplantation genetic is to screen
the chromosomes. Also, they experimented on the high-risk pregnancy. A couple having the previous
Drosophila Melanogaster and determined the nature of history of any genetic disorder can be suggested for
sex-linked traits. preimplantation genetics.
1923: Griffith F, experimented on bacteria and
postulated that the DNA is the genetic material.
CLINICAL GENETICS
1953: Watson and Crick identified the structure of DNA.
This genetic field is involved with the study of disease,
finding the root of the disease, its adverse, related effects,
and its inheritance pattern.
BRANCHES OF GENETICS
PLANT GENETICS
The branch of genetics that deals with the study of genetic
variation and chromosomal abnormalities in plants. The
mechanism of inheritance was developed from
experimenting with plants. The foundation of genetics laid
by experimenting on pea plant by father of genetics,
Mendel.
MICROBIAL GENETICS
Microbial genetics is an applied branch of genetics that
includes the study of the genes, genotypes ad gene
expression of microorganism for various genetic
engineering applications.
MOLECULAR GENETICS
Molecular genetics is an interdisciplinary sub-branch of
genetics dealing with the study of the structure and POPULATION GENETICS
function of DNA as well as genes (at a molecular level) An interdisciplinary branch of genetics that includes the
using techniques such as Polymerase chain reaction and study of genetic difference within and between the
DNA sequencing. population or individual.
,EPIGENETICS Separation is a process of extracting molecules like DNA
or mRNA from other cell debris. After that DNA is purified
The branch of genetics that deals with the study of using the ready to use-kit or using alcohol. Once the
alterations in an organism caused by gene expression purified – good quantity DNA is obtained, it is further
rather than alteration caused by a gene mutation. In processed for the downstream applications.
simple words, epigenetics is a study of gene expression.
PCR: The polymerase chain reaction is a process in
PHYSIOLOGICAL GENETICS which we can amplify millions of copies of a DNA segment
Physiological genetics deals with the study of of our interest in vitro. The process is temperature-
physiological characteristics such as sex differentiation dependent, and divided into three steps:
and sex determination, blood group factor and sickle cell
• Denaturation: the double-stranded DNA
anemia like physiological conditions.
denatured into a single-stranded one.
• Annealing: the Sequence-specific DNA primer
BIOCHEMICAL GENETICS binds/anneal to its complementary sequence on
single-stranded DNA.
The branch of the genetics related to studying the
chemistry of DNA, gene, chromosome, RNA and related • Extension: the Taq DNA polymerase amplifies
biomolecules. the DNA using the 3′ end of the primer.
QUANTITATIVE GENETICS
It is actually a branch of the population genetics which
studies the continuously varying phenotypes.
BEHAVIORAL GENETICS
This field of genetics study the behavioral phenotypes of
an organism governed by the genetic factors.
TECHNIQUES (TOOLS) USED IN THE STUDY
OF GENETICS
Using the molecular genetics techniques one can screen
pathogenic mutation, detect SNPs (single nucleotide
DNA CLONING
polymorphism), minor deletion or duplication at the DNA
level. further, gene expression studies are also possible DNA cloning is a traditional method for the synthesis of
using molecular genetic techniques. A state of the art DNA. Using a cloning vector our sequence of interest can
technique, DNA sequencing is powerful enough to find be synthesized by the bacterial artificial
new variations or mutations. Polymerase chain reaction, chromosome. The method is time-consuming and not so
gene cloning, DNA Sequencing and DNA quantification accurate. It includes tedious steps like cell culture and
are some of the techniques used in molecular genetic isolation.
analysis.
Any of the molecular genetic experiment divided into the
4 sub-steps: DNA SEQUENCING:
• Separation of molecule The method of reading the sequence of DNA using a
computational tool is called DNA sequencing. In this
• Purification of molecules method, we can actually analyze any variation or new
mutation in our sequence of interest using the fluoro-
• Processing of molecule labeled dNTPs.
• Detection of molecule
, CONCLUSION
In a broader sense, genetics is a study of genotype, its
related phenotype, and alterations in the genome. Using
genetics tools, nowadays, the diagnosis of inherited
diseases is a common medical practice.
The Human Genome Project was completed in the year
2013. Now we have the entire genomic sequence of
human. We can use this data for the identification of new
mutations and alterations.
Further, genomic data of so many other organisms are
now available which is used for identification and
characterization of different organisms and species.
