The document discusses various types of non-coding DNA sequences, including repetitive sequences, transposons, non-coding RNAs, introns, and pseudogenes. It notes that while genes only make up 2-3% of human DNA, recent projects like ENCODE have found that a much larger portion of non-coding DNA is functionally important, for example through transcriptional and translational regulation of protein-coding sequences. The document outlines different classes of transposons, introns, non-coding RNAs and their various roles in gene expression, epigenetics, and genome evolution.
Dna supercoiling and role of topoisomerasesYashwanth B S
supercoiling is one of the important process to condenses the huge amount of DNA to fit inside the histone and its also plays a role during the replication ,transcription etc..,these activities is carried out by an enzyme called topoisomerases.
Dna supercoiling and role of topoisomerasesYashwanth B S
supercoiling is one of the important process to condenses the huge amount of DNA to fit inside the histone and its also plays a role during the replication ,transcription etc..,these activities is carried out by an enzyme called topoisomerases.
Genomic library and shotgun sequencing. It includes the topics about genomic library,construction method, its uses and applications, shotgun sequencing, difference between random and whole genome sequencing, its advantages and disadvantages etc.
A detail ppt about Genome organization with focus on all levels of organization. Most recent research and findings about CT is also added in this ppt. Detail account of 30nm fiber and its ultra structure and types is also included.
Genomic library and shotgun sequencing. It includes the topics about genomic library,construction method, its uses and applications, shotgun sequencing, difference between random and whole genome sequencing, its advantages and disadvantages etc.
A detail ppt about Genome organization with focus on all levels of organization. Most recent research and findings about CT is also added in this ppt. Detail account of 30nm fiber and its ultra structure and types is also included.
This presentation provides an overview of What is a transposon,different types of transposons, their mechanism of action, examples for each type of transposons, changes caused due to insertion of transposon into the target gene and applications of Transposons. They are controlling factors in gene expression. Jumping genes is a special area of interest in Genetic research.
Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation, and expression of genes. RNA and DNA are nucleic acids, and, along with proteins and carbohydrates, constitute the four major macromolecules essential for all known forms of life. Like DNA, RNA is assembled as a chain of nucleotides, but unlike DNA it is more often found in nature as a single-strand folded onto itself, rather than a paired double-strand.
Gene Therapy, Somatic cell gene therapy, germ line gene therapy, classical gene therapy, non-classical gene therapy, targets of gene therapy, barriers of gene therapy, ex vivo gene therapy, in vivo gene therapy, vectors for gene delivery, antisense therapy
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
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
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.
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.
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
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.
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
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.
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists
Junk DNA/ Non-coding DNA and its Importance (Regulatory RNAs, RNA interference, Pseudogenes)
1. “Junk DNA” and
its importance
PRADEEP SINGH
M.Sc. Medical Biochemistry
HIMSR, Jamia Hamdard
2. JensMartensson
2
Content• Background
• Introduction
• Types of noncoding DNA sequences
1. Repetitive sequences
2. Transposons
3. Non-coding RNAs
4. Introns
5. Pseudogenes
6. Cis- and trans-regulatory sequences
• Regulation of Gene Expression
• Uses
Evolution
Long range correlations
Forensic anthropology
3. JensMartensson
Background
• The Human Genome is 3.2 billion base
pairs long and contains about 25,000 –
30,000 genes.
• These genes only make about 2-3% of our
DNA. The other 97-98% of our genome is
non-coding.
• The term “Junk DNA” was coined in 1960s
for non-coding DNA.
• In eukaryotes, genome size and the
amount of noncoding DNA, is not
correlated to organism complexity, an
observation known as the C-value
paradox. Examples: Amoeba dubia,
Utricularia gibba.
3
Fig: Amoeba dubia
Genome Size: 670 billion base
pairs
Fig: Utricularia gibba
Genome size: 82 million base pairs,
contains only 3% of non-coding
DNA
4. JensMartensson
• The Human Genome Project (1990-2003) : It is anticipated that
detailed knowledge of the human genome will provide new avenues for
advances in medicine and biotechnology.
• ENCODE: In 2012, the ENCODE project, a research program supported by
the National Human Genome Research Institute, reported that 80% of the
human genome is functional in some way. The human genome's
noncoding DNA sequences were transcribed and that nearly half of the
genome was in some way accessible to genetic regulatory proteins such
as transcription factors.
• Based on comparative genetics only 8 to 15% fraction of the human
genome is biologically functional.
4
5. JensMartensson
• Chromatin immunoprecipitation or ChIP-seq assays identify links between the
genome and the proteome by monitoring transcription regulation through histone
modification (epigenetics) or transcription factor–DNA binding interactions.
• Steps:
Step 1: Crosslinking (DNA-Protein inter)
Step 2: Cell lysis (protein–DNA extraction)
Step 3: Chromatin preparation (shearing/digestion)
Step 4: Immunoprecipitation
Step 5: Crosslinking reversal and DNA clean-up
Step 6: DNA quantification
ChIP-Seq
5
8. JensMartensson
Introduction
• “Junk DNA” or Non-coding
DNA sequences are components of an
organism's DNA that do
not encode proteins or polypeptides.
• Some noncoding DNA is transcribed into
functional non-coding RNA molecules
(e.g. transfer RNA, ribosomal RNA,
and regulatory RNAs).
• Other functions of noncoding DNA include
the transcriptional and translational regula
tion of protein-coding sequences, scaffold
attachment regions, origins of DNA
replication, centromeres and telomeres.
8
12. JensMartensson
2. Transposons
• The first transposons were discovered in maize (Zea mays), by
Barbara McClintok in 1948. Also known as “Jumping Genes.”
• Transposons are found in both prokaryotes and eukaryotes.
• In maize, they account for 85 percent of all the DNA.
• At least 44% of human genome consist of transposons. They clearly have roles in shaping the
structure of chromosomes and in modulating gene expression of genes.
• They can be classified into three categories:
1. Cut & Paste transposons: Transposition is accomplished by excising an element from its position
in a chromosome and inserting it into another position. (No increase in copy number) (Found in
both prokaryotes and eukaryotes)
2. Replicative transposons: Transposition is accomplished through a process that involves
replication of the transposable element’s DNA. During this interaction, the element is replicated
and one copy of it is inserted at the new site; one copy also remains at the original site. (Increase
in copy number) (Found only in prokaryotes)
3. Retrotransposons: Transposition is accomplished through a process that involves the insertion of
copies of an element that were synthesized from the element’s RNA by reverse transcriptase
which is then inserted into new chromosomal sites. (Increase in copy number) (Found only in
eukaryotes)
12
14. JensMartensson
Transposons Elements in Humans
• At least 44 percent of human DNA is derived from transposable elements,
including:
Retroviruslike Elements or LTR retrotransposons ~ 8%
Retroposons or non-LTR retrotransposons ~ 33%
Cut & Paste Transposons ~ 3%
• The priniciple transposable elements in human are retroposons. They are classified
into:
LINEs: Long Interspersed Nuclear Elements
SINEs: Short Interspersed Nuclear Elements
• LINEs are the most abundant retroposons in humans. They are further classified
into three subtypes:
L1: The human genome contain between 3000 to 5000 complete L1 elements
which are transpositionally active. In addition, more than 5,00,000 L1 elements that
are truncated at their 5’ ends i.e., transpositionally inactive. (Complete L1 elements are
about 6 kb long)
14
15. JensMartensson
• SINEs: SINEs are the second most abundant class of transposable elements
in the human genome. These elements are less than 400 base pair long
and do not encode proteins. Thus, SINEs depend on the LINEs to multiply
and insert within the genome.
• The human genome contain three families of SINEs, Alu, MIR and
Ther2/MIR3 elements. However, only the Alu elements are transpositionally
active.
• Importance:
* In human embryos, two types of transposons (DNA transposons & Retrotransposons) combined
to form non-coding RNA that catalyzes the development of stem cells. During the early stages of
a fetus’s growth, the embryo’s inner cell mass expands and give rise to all cells in the body.
* Transposable elements are mutagens and their movements are often the cause of genetic
disease. Diseases often caused by transposable elements include Hemophilia A and B, SCID,
Porphyria, colon cancer and Duchenne muscular dystrophy.
* The Sleeping Beauty transposon system is a synthetic DNA transposon designed to introduce
precisely defined DNA sequences into the chromosomes of vertebrate animals for the purposes
of introducing new traits and to discover new genes and their functions. It is being investigated
for use in human gene therapy.
* Cells defend against the proliferation of transposable elements in a number of ways. These
include piRNAs and siRNAs, which silence transposable elements after they have been
transcribed.
15
16. JensMartensson
3. Introns
• The word intron is derived from the term intragenic region, i.e. a region
inside a gene.
• The term intron refers to both the DNA sequence within a gene and the
corresponding sequence in RNA transcripts.
• Many genes like interferons, histons genes, ribonuclease genes (many), heat
shock protein genes, G protein coupled receptors (many) lack introns.
• Types of Introns:
16
Type of intron Gene type Splicing Mechanism
tRNAs and rRNAs tRNA genes Enzymatic
Nuclear (pre-mRNA) Protein-encoding genes
in nuclear chromosomes
Spliceosomal
Group I Some rRNA genes Self-splicing
Group II Protein-encoding genes
in mitochondria
Self-splicing
17. JensMartensson
Alternate Splicing
17
• RNA splicing was first discovered in 1970s
in viruses and subsequently in eukaryotes.
• Alternative splicing therefore is a process
by which exons or portions of exons or
noncoding regions within a pre-mRNA
transcript are differentially joined or
skipped, resulting in multiple protein
isoforms being encoded by a single gene.
• The first example of alternative splicing of
a cellular gene in eukaryotes was identified
in the IgM gene, a member of the
immunoglobulin superfamily.
• Another well known example of alternate
splicing in human include the troponin T
gene.
19. JensMartensson
RNA
function
RNA type Detailed role in the cell
Protein
synthesis
Transfer RNA
(tRNA)
Ribosomal
RNA (rRNA)
Adapter molecule bringing the amino acid
corresponding to a specific mRNA codon to the
ribosome. Having an anticodon (complimentary
to the codon), a site binding a specific amino
acid and a site binding aminoacyl-tRNA
synthetase (enzyme catalyzing amino acid-tRNA
binding).
RNA components of the ribosome, where
protein is translated. Ribosomes align the
anticodon of tRNA with the mRNA codon and
are required for the peptidyl transferase activity
catalyzing the assembly of amino acids into
19
20. JensMartensson
20
RNA
interference
(RNAi)/ Gene
silencing
Micro RNA
(miRNA)
Small (short)
interfering RNA
(siRNA)
Piwi-interacting
RNA (piRNA)
Endogenous, small, single-stranded RNAs inducing gene silencing by
binding to target sites found within the 3’UTR of the targeted mRNA,
resulting in translation repression or mRNA degradation. Regulating
processes like cell cycle, apoptosis, etc., and implicated in a number of
diseases.
Exogenous, short, double-stranded RNAs interfering with the
expression of specific genes with complementary nucleotide
sequences by inducing mRNA cleavage, resulting in no translation.
Short, single-stranded RNAs that are part of riboprotein complexes
active in the germ line, ensuring germ-line stability by silencing
transposons within germ cells. Occurring in clusters encoding 10 to
thousands of individual piRNAs throughout the mammalian genome.
RNA
function
RNA type Detailed role in the cell
21. JensMartensson
21
RNA interference (RNAi)
• RNAi is an evolutionary is an evolutionary conserved mechanism of gene regulation
that is induced by small silencing RNA in a sequence-specific manner.
• The phenomenon was first identified in C. elegans by Fire and Mello in 1998. Lin-4 and
Let-7 are two micro-RNAs (miRNAs) that were first discovered in C. elegans.
• Two principle types of small silencing RNA molecules are:
i. microRNA (miRNA) [endogenously produced]
ii. small interfering RNA (siRNA) [exogenously produced]
• These small RNAs have been shown to play critical roles in developmental timing,
haematopoietic cell differentiation, cell death, cell proliferation and oncogenesis.
22. JensMartensson
22
miRNAs mediated RNA
interference• miRNAs are synthesized in
the nucleus as long
transcripts, called pri-
miRNAs, that are
characterized by imperfect
hairpin structures.
• Drosha (RNase III) acts in
conjugation with ds-RNA
binding protein called
DGCR8 (in mammals) or
Pasha (in Drosophila) on pri-
mRNA and convert it into
pre-miRNA.
• Pre-miRNAs also contain
introns known as mirtrons.
~ 1000
nucleotides
70-100 nucleotides
Exportin 5
18-22 nucleotides
Rnase III
• Pre-miRNAs are transported to the cytoplasm by exportin-5 proteins in the nuclear membrane.
• Pre-miRNA is converted into miRNA duplex by Dicer. It also load it into RISC (RNA Induced
Silencing Complex).
23. JensMartensson
23
miRNAs mediated RNA
interference• RISC is composed of a family of proteins known as Argonaute (Ago) protein family.
• Argonautes are needed for mi-RNA induced silencing and contain two conserved RNA binding
domains:
i. PAZ domain: Binds single stranded 3’ end of mature miRNA.
ii. PIWI domain: Structurally resembles RNase H.
• miRNAs function via base-pairing with complementary sequences within target mRNA
molecule.
• Gene silencing occur by either via mRNA degradation or preventing mRNA from being
translated.
• If there is complete complementation, between miRNA and target mRNA sequence, Ago can
cleave the mRNA and lead to direct mRNA degradation.
• If there is incomplete complementation, then silencing is achieved by preventing translation.
24. JensMartensson
24
siRNAs mediated RNA interference
siRNA versus miRNA
• siRNAs are processed from dsRNA precursors
made up of two distinct strands of perfectly
base-paired RNA, while miRNAs originate from a
single, long transcript that forms imperfectly
base-paired hairpin structures.
• Mechanism of action is same.
• piRNAs (Piwi-interacting RNAs) are the most
recently discovered class of longer small RNAs
(~25-30 nucleotides) which bind to the Piwi
clade of argonaute proteins.
piRNAs
25. JensMartensson
5. Pseudogenes
• Pseudogenes refers to a segment of DNA that are related to real genes but are non-
functional. The term ‘”pseudogenes” was coined in 1977 by Jacq et al.
• Pseudogenes often result from the accumulation of multiple mutations within a
gene whose product is not required for the survival of the organism.
• Pseudogenes can complicate molecular genetic studies. For example, amplification
of gene by PCR may simultaneously amplify a pseudogene that shares similar
sequences. This is known as PCR bias or amplification bias.
• Types and Origin: There are four main types of pseudogenes.
I. Processed Pseudogenes
II. Non-processed Pseudogenes
III. Unitary Pseudogenes
IV. Pseudo-seudogenes
25
26. JensMartensson
26
1. Processed Pseudogenes
• Processed (or retrotransposed)
pseudogenes.
• In the process of processed transposons,
primary transcript (hnRNA) of a gene is
processed into mature mRNA.
• The mature mRNA is spontaneously
reverse transcribed back into cDNA.
• Double stranded DNA is synthesized from cDNA and inserted into the chromosomal DNA.
• Processed transposons usually contain a poly-A tail. They also lack the upstream promoters of
normal genes. Therefore, they cannot be transcribed again.
27. JensMartensson
27
II. Non-processed Pseudogenes
• Non-processed (or duplicated
pseudogenes)
• Gene duplication is another common and
important process in the evolution of
genomes caused by homologous
recombination.
• For example, repetitive SINE sequences on
misaligned chromosomes and
subsequently acquire mutations that cause
the copy to lose the original gene’s
function.
• Gene duplication generates
functional redundancy and it is not
normally advantageous to carry two
identical genes.
• According to some evolutionary models, shared duplicated pseudogenes indicate the
evolutionary relatedness of humans and the other primates.
28. JensMartensson
28
III. Unitary Pseudogenes
• Unitary transposons or disabled transposons.
• Various mutations (such as indels and nonsense
mutations) can prevent a gene from being
normally transcribed or translated, and thus the
gene may become less- or non-functional or
"deactivated".
• The mechanisms is same like non-processed
genes become pseudogenes, but the difference
in this case is that the gene was not duplicated
before pseudogenization.
• The classic example of a unitary pseudogene is
the gene that presumably coded the enzyme L-
gulono-γ-lactone oxidase (GULO) in primates.
In all mammals studied besides primates
(except guinea pigs), GULO aids in the
biosynthesis of ascorbic acid (vitamin C), but it
exists as a disabled gene (GULOP) in humans
and other primates.
30. JensMartensson
30
IV. Pseudo-pseudogenes
• Pseudogenes are generally considered
to be non-functional DNA sequences
that arise from protein-coding genes.
• Pseudogenes are often identified by
the appearance of a premature stop
codon in a predicted mRNA sequence.
• A small amount of protein product of
such mRNA sequence may still be
recognizable and function at some
level.
• In 2016, it was reported that 4
predicted pseudogenes in multiple
Drosophila species actually encode
proteins with biologically important
functions.
• Example: Olfactory receptors found
only in neurons in some species of
Drosophila.
33. JensMartensson
6. Cis- and Trans-regulatory
Elements• Cis-regulatory elements: Cis-regulatory elements are regions of non-coding DNA which
regulate the transcription of neighboring genes. Cis-elements may be located in 5' or 3‘
untranslated regions (UTRs) or within introns. Many such elements are involved in the
evolution and control of development.
• Trans-regulatory elements: Trans-regulatory elements are regions of non-coding DNA
sequences that encode transcription factors which may modify (or regulate) the
expression of distant genes.
Examples of trans-acting factors include the genes for:
I. Subunits of RNA polymerase
II. Proteins that bind to RNA polymerase to stabilize the initiation complex
III. Proteins that bind to all promoters of specific sequences, but not to RNA polymerase (TFIID
factors)
IV. Proteins that bind to a few promoters and are required for transcription initiation (positive
regulators of gene expression)
33
35. JensMartensson
Regulation of Gene Expression
• Some noncoding DNA sequences determine the expression levels of various genes, both
those that are transcribed to proteins and those that themselves are involved in gene
regulation.
• Transcription factors
Some noncoding DNA sequences determine where transcription factors attach.[55] A transcription factor
is a protein that binds to specific non-coding DNA sequences, thereby controlling the flow (or
transcription) of genetic information from DNA to mRNA.
• Operators
An operator is a segment of DNA to which a repressor binds. A repressor is a DNA-binding protein that
regulates the expression of one or more genes by binding to the operator and blocking the attachment
of RNA polymerase to the promoter, thus preventing transcription of the genes. This blocking of
expression is called repression.
• Enhancers
An enhancer is a short region of DNA that can be bound with proteins (trans-acting factors), much like
a set of transcription factors, to enhance transcription levels of genes in a gene cluster.
35
36. JensMartensson
36
• Silencers
A silencer is a region of DNA that inactivates gene expression when bound by a regulatory
protein. It functions in a very similar way as enhancers, only differing in the inactivation of genes.
• Promoters
A promoter is a region of DNA that facilitates transcription of a particular gene when a
transcription factor binds to it. Promoters are typically located near the genes they regulate and
upstream of them.
• Insulators
A genetic insulator is a boundary element that plays two distinct roles in gene expression, either
as an enhancer-blocking code, or rarely as a barrier against condensed chromatin. An insulator in
a DNA sequence is comparable to a linguistic word divider such as a comma in a sentence,
because the insulator indicates where an enhanced or repressed sequence ends.
38. JensMartensson
Uses of “Junk” DNA
• Evolution
Shared sequences of apparently non-functional DNA are a major line
of evidence of common descent
Pseudogene sequences appear to accumulate mutations more rapidly than
coding sequences due to a loss of selective pressure. This allows for the
creation of mutant alleles that incorporate new functions that may be
favored by natural selection; thus, pseudogenes can serve as raw material
for evolution and can be considered "protogenes".
• Mapping the distance between functional genes
• Forensic anthropology
Police sometimes gather DNA as evidence for purposes of forensic
identification.
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Amoeba dubia is a protozoan, is one of the largest genome organism.
Do prokaryotes have non-coding DNA?
Encyclopedia of DNA elements
ChiP-seq is a way to isolate the DNA where a particular transcription factor binds which can later be sequenced.
Molecular biologists and Evolutionary Biologists
Mnase or Monococcal Nuclease
Protein Scaffold:
rRNA genes because ribosomes are required for rapid protein synthesis during various phases of cell cycle.
The excision and insertion events are catalyzed by an enzyme called transposase, which is usually coded by the enzyme itself.
Selfish DNA: The DNA that replicates but have no use to the host cell it inhabits.
Cut & Paste Transposons in eukaryotes includes P-element in Drosophila.
Tc1/mariner is a class and superfamily of interspersed repeats DNA (Class II) transposons. The elements of this class are found in all animals including humans.
Sleeping beauty system, awarded Molecule of the Year in 2009.
Two transesterification reaction:
Nuclear pre-mRNA contains A at the branch site
Group I Introns contains G at the branch site
Group II Introns contains A at the branch site
Group I Introns releases a Linear Intron Rather than a Lariat
Drosha and DGCR8 are microprocessor complex that helps in the processing of pri-mRNA.
Drosha/Pasha: ds-RNA binding protein called pasha (in Drosophila) and DGCR8 (in mammals).
Drosha and DGCR8 are microprocessor complex that helps in the processing of pri-mRNA.
Drosha/Pasha: ds-RNA binding protein called pasha (in Drosophila) and DGCR8 (in mammals).
Gene redundancy is the existence of multiple genes in the genome of an organism that perform the same function.
Indel is a molecular biology term for an insertion or deletion of bases in the genome of an organism.
These are the same mechanisms by which non-processed genes become pseudogenes, but the difference in this case is that the gene was not duplicated before pseudogenization.
Another example include the GPCRs that binds to ligands but their function is unknown. We call them as Pseudogenes.
Recently 140 human pseudogenes have been shown to be translated. However, the function, if any, of the protein products is unknown.