An overview on mutation, the general mechanisms, classification based on various characteristics, analogy sentence and genetic disorder of various types based on its classification, a brief description of mutagens agents and consequences of mutation in our body and on other living creatures
Techniques based on the principle of selectively amplifying a subset of restriction fragments from a complex mixture of DNA fragments obtained after digestion of genomic DNA with restriction endonucleases.
This presentation deals with DNA replication in mamalian mitochondria. Mammalian mtDNA is replicated by proteins distinct from those used for nuclear DNA replication. According to the strand displacement model, replication is initiated from two distinct origins, OH and OL.
A cytological technique to detect the nature of adjacent chromosomal regions by using different staining technique assisted with some pre treatment of metaphase chromosomes prepared on the slides
Techniques based on the principle of selectively amplifying a subset of restriction fragments from a complex mixture of DNA fragments obtained after digestion of genomic DNA with restriction endonucleases.
This presentation deals with DNA replication in mamalian mitochondria. Mammalian mtDNA is replicated by proteins distinct from those used for nuclear DNA replication. According to the strand displacement model, replication is initiated from two distinct origins, OH and OL.
A cytological technique to detect the nature of adjacent chromosomal regions by using different staining technique assisted with some pre treatment of metaphase chromosomes prepared on the slides
mutations Is a process that produces a gene or chromosome that differs from the wild type.
The mutation may result due to changes either on the gene or the chromosome itself.
mutation
history of mutation
classification of mutation
types of mutation
syndrome due to mutation
chromosomal variations in number
causes of mutation to occur
mutagen types
Gene mutations – introduction – definition – a brief history – terminology –
classification of mutations – characteristic features of mutations – spontaneous
mutations and induced mutations
Gene mutations – artificial induction of mutations – physical and chemical
mutagens – molecular basis of mutations – detection of sex-linked lethals in
Drosophila by CLB technique – detection of mutations in plants – the importance of
mutation in plant breeding programmes –
NVBDCP.pptx Nation vector borne disease control programSapna Thakur
NVBDCP was launched in 2003-2004 . Vector-Borne Disease: Disease that results from an infection transmitted to humans and other animals by blood-feeding arthropods, such as mosquitoes, ticks, and fleas. Examples of vector-borne diseases include Dengue fever, West Nile Virus, Lyme disease, and malaria.
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Hemodialysis: Chapter 3, Dialysis Water Unit - Dr.Gawad
Mutation
1. Mutation Overview
Saad Ahmed Sami, Dept. of Pharmacy, CU
Page | 1
Mutation
Mutation is any sudden and abrupt changes to the genetic or hereditary material of an organism.
These changes occur suddenly and mostly unexpected. The changes are usually random and
disruptive to the normal functioning of the body. A single nucleotide pair or larger gene segment
of a chromosome can be affected by mutation that may result in different phenotype than normal
leading to genetic variation. Genetic variation may result in genetic disorder as well. Animals,
Fungi, Plants as well as viruses exhibit mutations.
So, we may define mutation as the spontaneous changes that affect the DNA or the genes or
sometimes complete chromosome.
Depending upon the type of mutation that has occurred, treatment may be possible. Cancer is a
disease caused by mutations and is treatable through radiation and chemotherapy. Another
disease caused by mutated cells is Sickle Cell Anemia which has treatment methods being used
currently, but still no cure.
Mutations can be inherited.
This means that if a parent has a mutation in his or her DNA, then the mutation is passed on to
his or her children. Only mutations in gametes are passed onto the offspring. Mutations in the
body cells only affect the organism in which they occur and are not passed onto the offspring.
Mutations can be acquired.
This happens when environmental agents damage DNA, or when mistakes occur when a cell
copies its DNA prior to cell division.
Some Terminologies
Individuals showing changes due to mutation are known as mutants.
Individuals showing an altered phenotype due to mutation are known as variants.
Factors or gene causing mutations are known as mutagens.
2. Mutation Overview
Saad Ahmed Sami, Dept. of Pharmacy, CU
Page | 2
Characteristics of Mutation
1. Generally mutant alleles are recessive to their wild type or normal alleles.
2. Most mutations have harmful effect, but some mutations are beneficial.
3. Spontaneous mutations occur at very low rate.
4. Some genes shows high rate of mutation such genes are called as mutable gene.
5. Highly mutable sites within a gene are known as hot spots.
6. Mutation can occur in any tissue/cell (somatic or germinal) of an organism.
Molecular Mechanisms of Mutation
Mutations arise in two ways:
(A) During DNA replication, double strands of DNA are separated. Each strand is then copird to
become another double strand. About 1 out of every 100,000,000 times, a mistake occurs during
copying, which can lead to a mutation.
Some mutations are spontaneous errors in replication that evade the proofreading function of the
DNA polymerases that synthesize new polynucleotides at the replication fork These mutations
are called mismatches because they are positions where the nucleotide that is inserted into the
daughter polynucleotide does not match, by base pairing, the nucleotide at the corresponding
position in the template DNA (Figure A). If the mismatch is not corrected in the daughter double
helix then one of the granddaughter molecules produced during the next round of DNA
replication will carry a permanent, double-stranded version of the mutation.
(B) Other mutations arise because a mutagen has reacted with the parent DNA, causing a
structural change that affects the base-pairing capability of the altered nucleotide. Usually this
alteration affects only one strand of the parent double helix, so only one of the daughter
molecules carries the mutation, but two of the granddaughter molecules produced during the next
round of replication will have it (Figure B).
Mutagenic agents are usually classified as chemical or physical mutagens.
3. Mutation Overview
Saad Ahmed Sami, Dept. of Pharmacy, CU
Page | 3
I. Physical Mutagens
Radiation
Ionizing ( e.g. X-ray, gamma ray, cosmic ray)
Non-ionizing (e.g. UV ray)
Heat
Break the N-glycosidic bond in DNA
Result from apurinic site or base less site
II. Chemical Mutagens
Base analogues: Hydroxylamine, 5-Bromouracil, 2-Aminipurine
Intercalating agents: Aflatoxin, Benzopyrene, Ethidium bromide
Alkylating agents: Nitrogen, Mustard, Ethylene oxide
4. Mutation Overview
Saad Ahmed Sami, Dept. of Pharmacy, CU
Page | 4
Consequences of Mutation
Mutations can be-
1) Helpful:
Helpful Mutations improve the organism’s chance for survival, reproduction and diversity
Examples of Helpful Mutations can be Poison Dart Tree Frog. Poison dart frogs are
normally bright blue, red or yellow in color. Mutations making it green in color resulting
in helpful mutation because it can’t be easily seen among the green trees. Therefore, it
has an increased chance of surviving because predators can’t see it easily.
Increase biodiversity, turn off harmful genes and produce new version of protein that can
be essential for evolution.
Hemoglobin in the RBC carries O2. But in case of an individual who inherits one copy of
mutated gene, they don’t have the disease sickle cell anemia, instead they show
protective response against malaria. Even if they get malaria, their symptoms are less
severe.
5. Mutation Overview
Saad Ahmed Sami, Dept. of Pharmacy, CU
Page | 5
Scorpion with an extra stinger
2) Harmful:
They reduce the organism’s chance for survival and reproduction.
Any mutation can lead to diseases such as Cancer- overexposure to UV-light, Cystic
fibrosis , Turners syndrome, Sickle-Cell Disease ,Hemophilia ,Down Syndrome.
Protein malfunction and stop the fetus development.
The mutation of bacteria can lead to antibiotic resistance that is also harmful for us.
In case of an albino tree frog, It has a harmful mutation because it can be easily seen
among the green trees. Therefore, it has a decreased chance of surviving because
predators can see it easily.
3) Neutral (No Effect):
These mutations do not show any advantages or disadvantages to an organism. In fact, many
organisms may have mutated genes and not know it because it does not show through on its
phenotype and does not affect the structure or function of the gene in the cell at all. We consider
a codon CUU codes for leucine. Suppose, it gets mutated and transformed to CUC that still codes
for leucine. It is a silent mutation. Silent mutation is an example of Neutral Mutation.
Classification of Mutation
If we consider a small section of DNA, one base may be deleted or inserted. So, the sequence of
gene will change resulting in change in the reading frame. Any change in the single nucleotide
will change the entire codon. So, it will alter the gene and give rise to defective protein
(harmful). We can divide the mutation based on the genetic material and chromosome.
6. Mutation Overview
Saad Ahmed Sami, Dept. of Pharmacy, CU
Page | 6
A) Chromosomal Mutation:
It can be divided into two types-
i) Chromosomal aberrations: Based on the alteration of structure of Chromosome.
ii) Aneuploidy: Based on the alteration of number of Chromosome.
Chromosomal aberrations
Once a normal chromosomal structure gets altered, it is called chromosomal aberrations. These
are described below-
Deletion: Small part removed due to breakage. A piece of chromosome segment is lost.
As a result segment having important gene is also lost. It can lead to severe
abnormalities. Example include- William’s syndrome, Wolf- Hirschhorn syndrome.
Duplication: Here, Part of chromosome is duplicated resulting in the increase of the
chromosome length. This can lead to severe abnormalities. Example include- Charcot-
Marie-Tooth disease.
Inversion: Chromosome segment breaks off and the segment flips around backwards and
reattaches. It may or may not be harmful depending on the gene which gets flipped.
7. Mutation Overview
Saad Ahmed Sami, Dept. of Pharmacy, CU
Page | 7
Insertion: A part of the Chromosome gets inserted to another chromosome. Both the
chromosome change drastically resulting in severe abnormalities.
Translocation: Involves two chromosomes that are not homologous. A segment from
each chromosome gets inter exchanged. Abnormalities occur as both the chromosome
altered completely. Example include- XX male syndrome.
Aneuploidy
It means change in the number of chromosome. Abnormal number of chromosome is present in
the cell. It can occur in both sex chromosome and autosome.
Types of Aneuploidy:
a) Nullisomy: loss of a chromosome pair ( 2 chromosomes)
b) Monosomy: loss of a single chromosome
c) Trisomy: Addition of an extra chromosome
8. Mutation Overview
Saad Ahmed Sami, Dept. of Pharmacy, CU
Page | 8
d) Tetrasomy: Addition of two extra chromosomes
Examples include-
Down syndrome: It is caused by trisomy 21, that is the addition of an autosome in the
21st
chromosome. It alters the chromosome number (2n=47)
Klinefelter syndrome: Individuals having an additional X chromosome in their sex
chromosome resulting in Klinefelter syndrome. It is the presence of both masculine and
feminine characteristics. It alters the chromosome number (2n=47)
Turner syndrome: It is the deletion of an X chromosome in the sex chromosome in
women resulting in Turner syndrome. It alters the chromosome number
(2n=45).
9. Mutation Overview
Saad Ahmed Sami, Dept. of Pharmacy, CU
Page | 9
It also include Edwards Trisomy 18 (addition of an autosome in the 18th
chromosome), Jacob’s
Syndrome in Men (XYY, 2n=47) and many other diseases as well.
B) Genetic Mutation:
EFFECTS OF GENE MUTATIONS
i. Most mutations are neutral they have no effect on the polypeptide.
ii. Some mutations result in a less active product;
iii. Less often an inactive product;
iv. Very few mutations are beneficial.
v. Affects molecular changes in the DNA sequence of a gene
vi. Alter the coding sequence within a gene
vii. Causes permanent change in DNA sequence
Genetic mutation can be of 3 types,
Point mutations: A change in the DNA sequence at a single base pair.
Silent: Silent mutation single base substitution in the 3rd
base nucleotide position
of a codon. This results in no change in amino acid. The first 2 letters of the
genetic code are the most critical.
Nonsense: Single base substitutions that change a normal codon to a
termination/stop codon. There are 3 nonsense codons in the genetic code. It means
no protein.
10. Mutation Overview
Saad Ahmed Sami, Dept. of Pharmacy, CU
Page | 10
Missense: Single base substitution in 1st or 2nd base nucleotide position. This
results in changed amino acid. This is equivalent to changing one letter in a
sentence. Example: Sickle-cell anemia
Conservative- No change in the nature of the amino acid
Non- Conservative- Change in the nature of the amino acid
Base substitution mutation: The replacement of one base pair to another.
11. Mutation Overview
Saad Ahmed Sami, Dept. of Pharmacy, CU
Page | 11
Transitions: when a purine is replaced with a purine, or a pyrimidine with a pyrimidine.
Transversions: when a purine is replaced with a pyrimidine, or vice versa.
Frameshift mutations: Mutations in which a single base is added or deleted from DNA.
Adding/deleting one base changes every amino acid in the protein after. Our cells read
DNA in three letter "words", adding or removing one letter changes each subsequent
word. This type of mutation can make the DNA meaningless and often results in a
shortened protein & non-functional.
It can occur by two ways-
Addition or Insertion
Deletion
13. Mutation Overview
Saad Ahmed Sami, Dept. of Pharmacy, CU
Page | 13
Other Basis of classification:
Based on the survival of an individual
I. Lethal mutation- when mutation causes death of all individuals undergoing mutation
are known as lethal. It is the most extreme example of deleterious mutations.
II. Sub lethal mutation - causes death of 90% individuals.
III. Sub vital mutation- such mutation kills less than 90% individuals.
IV. Vital mutation -when mutation doesn't affect the survival of an individual are known
as vital.
V. Supervital mutation - This kind of mutation enhances the survival of individual. This
is a beneficial mutation.
Based on causes of mutation
I. Spontaneous mutation- Spontaneous mutation occurs naturally without any cause. The
rate of spontaneous mutation is very slow eg- Methylation followed by deamination of
cytosine. Rate of spontaneous mutation is higher in eukaryotes than prokaryotes.
Example-. UV light of sunlight causing mutation in bacteria.
II. Induced Mutation- Mutations produced due to treatment with either a chemical or
physical agent are called induced mutation. The agents capable of inducing such
mutations are known as mutagen. use of induced mutation for crop improvement program
is known as mutation breeding. Example- X-rays causing mutation in cereals.
Based on tissue of origin
I. Somatic mutation- A mutation occurring in somatic cell is called somatic mutation. In
asexually reproducing species somatic mutations transmits from one progeny to the next
progeny.
II. Germinal Mutation- When mutation occur in gametic cells or reproductive cells are
known as germinal mutation. In sexually reproductive species only germinal mutation are
transmitted to the next generation.
14. Mutation Overview
Saad Ahmed Sami, Dept. of Pharmacy, CU
Page | 14
Based on direction of mutation
I. Forward mutation- When mutation occurs from the normal/wild type allele to mutant
allele are known as forward mutation.
II. Reverse mutation- When mutation occurs in reverse direction that is from mutant allele to
the normal/wild type allele are known as reverse mutation.
Based on the type of trait affected
I. Visible mutation- Those mutation which affects on phenotypic character and can be
detected by normal observation are known as visible mutation.
II. Biochemical mutation- mutation which affect the production of biochemicals and which
does not not show any phenotypic character are known as biochemical mutation.
Based on the second site of mutation
These second-site mutations are called suppressor mutations or simply suppressors.
I. Intragenic suppressors- The second mutant site is within the same gene as the first
mutation
II. Intergenic suppressors- The second mutant site is in a different gene from the first
mutation