This document discusses DNA fingerprinting, including what it is, how it works, and its uses. DNA fingerprinting is a forensic technique that identifies individuals by characteristics of their DNA using variable tandem repeats. It was invented in 1985 and involves extracting DNA from samples, amplifying it, separating fragments by size via electrophoresis, and comparing band patterns to identify matches. DNA fingerprinting is used for paternity testing, criminal investigations, medical identification, and other applications like solving wildlife crimes and identifying mass casualties. Famous cases that have been solved using this technique include proving Steve Bing's paternity and catching the serial killer Colin Pitchfork.
DNA fingerprinting is a research facility procedure used to set up a connection between natural proof and a suspect in a criminal examination. A DNA test taken from a wrongdoing scene is contrasted and a DNA test from a suspect. On the off chance that the two DNA profiles are a match, at that point the proof originated from that suspect. On the other hand, on the off chance that the two DNA profiles don't coordinate, at that point the proof can't have originated from the suspect. DNA fingerprinting is likewise used to build up paternity.
DNA fingerprinting is a research facility procedure used to set up a connection between natural proof and a suspect in a criminal examination. A DNA test taken from a wrongdoing scene is contrasted and a DNA test from a suspect. On the off chance that the two DNA profiles are a match, at that point the proof originated from that suspect. On the other hand, on the off chance that the two DNA profiles don't coordinate, at that point the proof can't have originated from the suspect. DNA fingerprinting is likewise used to build up paternity.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
The power of dna fingerprinting in forensic science
1.
2. CONTENTS
Introduction to DNA.
What is DNA fingerprinting?
Sources of DNA .
Steps in DNA Fingerprinting.
Uses of DNA Fingerprinting.
Famous cases.
3.
4. WHAT IS DNA FINGERPRINTING?
DNA Fingerprinting is a forensic
technique used to identify
individuals by characteristics of
their DNA.
This technique is based on the
nucleotide sequence of a DNA
molecule.
The process of DNA Fingerprinting
was invented by Alec Jeffrey at the
university of Leicester in 1985.
Every person show an unusual
sequence of 20-100 base pairs which
are repeated several times, they are
termed as variable number of
tandem repeats(VNTR).
The length of the regions having
VNTRs are different in every
individual, this unique detectable
pattern is the key factor in DNA
profiling.
EXTRACTION is the process in which
the DNA are release from the cell.
Amplification is the process of
producing multiple copies of the DNA.
Separation is the process of separating
amplified DNA product to permit
subsequent identification.
Analysis & Interpretation is the process of
quantitatively and qualitatively comparing
DNA evidence samples to known DNA
profiles.
Quantitation is the process of
determining how much DNA you have
6. STEPS IN DNA FINGERPRINTING
1) DNA Isolation
• Various material available like blood,semen,hair roots,tissue,teeth,bones,saliva
samples etc. is treated with chemicals /enzymes to extract DNA, which then
separated & purified.
3) DNA Cutting
• The DNA is cut into fragments using restriction
enzymes.
• Each restriction enzymes cuts DNA at a specific
base sequence.
• This is called as Restriction Fragment Length
polymorphism (RFLP).
2)DNAAmplification
• If the DNA quantity is small it is subjected to in vitro replication by a
technique called PCR to obtain more copies of DNA .
7. 4) Electrophoresis: Electrophoretic separation of different fragments.
• Fragments are separated on the basis of
size using a process called gel
electrophoresis.
• DNA fragments are injected into the wells
and an electric current is applied along the
gel.
• DNA is negatively charged so it is
attracted to the positive end of the gel.
• The shorter DNA fragments move faster
than the longer fragments.
• DNA is separated on basis of size.
5) Transfer DNA on nylon /nitrocellulose
membrane
• Bands are transferred o the nylon
membrane. The single stranded
DNA get embedded into nylon
membrane.
8. 6) HYBRIDIZATION
• Adding radioactive or colored probes to the
nylon sheet which is complementary to target
sequences.
• Each probe sticks to one or two specific places
on the sheet.
7) AUTORADIOGRAPHY
• The DNA bands due to radioactive probe give
photographic image on X ray film.
• It shows multiple number of bands that look
like bar codes and known as DNA fingerprints.
8) INTERPRETATION OF BAND PATTERNS
Analysis of band patterns of different individuals
Comparison of position of bands
Computer software are also available for the analysis of DNA fingerprinting
9. APPLICATION OF DNA FINGERPRINTING
1) Paternity Test
A child inherits 1 set of genes from mother
and 1 set from father.
½ of the bands in a pattern are from mother
and the other from father.
Mitochondrial DNA mt.DNA is a
maternally inherited genetic material.
Nuclear DNA when not in sufficient amount
, mtDNA is used for forensic.
2) Diagnosis of inherited Disorders
Helps diagnose disorders in both prenatal and new born
babies
Disorders may include cystic
fibrosis,hemophilia,Hungtington’s diseases,familiar
Alzheimer’s, sickle cell anemia,thalassemia,and much more.
10. 3. Crime Investigation
Especially in murder or man-slaughter, sexual offences,assaults,robbery,house-
breaking,burglary,kidnapping,etc.
4. Solving medical problems
DNA profiles can be used to determine whether a particular person is the
parent of a child.
A child’s paternity (father) and maternity (mother) can be determined.
This information can be used in the cases of paternity suits, inheritance cases,
immigration cases.
5. Wildlife crime :-
Solving the cases of poaching, inbreeding, cure of genetics diseases, etc.
6. Natural & Man made disasters
Identification of mass casualties during earthquakes, floods, air crashes, train
accidents, explosions, fire, specially identification of the mutilated bodies in
such incidences.
11. FAMOUS CASES SOLVED USING DNA FINGERPRINTING
In 2002, Elizabeth Hurley used DNA
fingerprinting to prove that Steve Bing was the
father of her child Damien.
Colin Pitchfork was the first criminal caught
based on DNA fingerprinting evidence.
He was arrested in 1986 for the rape and
murder of two girls and was sentenced in 1988.