Forensic Bio Exam 3

The structure of DNA can be described as a

Double Helix

DNA is packaged tightly, helped by proteins called

Histones

The key difference in DNA that determines if an organism is going to be a human or a flower is the  

genetic instructions

What is the Nucleus

a large membrane bound organelle that contains the cells genetic material in the form of dna

What is one characteristic of YSTR

Y chromosome short tandem repeat, extends range of cases accessible to obtaining probative dna results, technical simplicity due to allele profile can recover dna from smaller samples and courts have widely accepted strs,

Is YSTR through the maternal or paternal line

Paternal, father to son

PCR name

Polymerase Chain Reaction

What happens to DNA during PCR

DNA is amplified (copies are made) of a specific loci

What are the names of DNAs nitrogenous bases

Adenine, Thymine, Guanine, Cytosine

What is a polymer

a polymer is a large molecule that is made up of smaller monomers

What is a monomer

a small basic molecular unit that can form polymers

Anti parallel dna

strands are parallel but run in opposite direction, 

5’ end to 3’ end then 3’ end to 5’ end 

How many nucleotide base pairs do humans have according to The Innocence Project?

3 billion nucleotide base pairs

Who were the contributing scientists, in the 1950’s who pioneered the work on DNA structure?

James Watson, Francis Crick who based their work on Rosalind Franklin and Maurice Wilkins 

Who are Watson, Crick, Wilkins and Franklin in relation to DNA structure research?

Watson and Crick discovered DNA structure and Fraklin used Xray crystallogy to visualizes the molecular structure which w and c used to create the model of DNA structure

What does the Innocence Project’s work focus on?

Cases that have DNA as an option to clarify innocence or guilt in a case

At what institution was the Innocence project first established?

Benjamin Cardozo School of Law

The work of the Innocence Project primarily focuses on what as an option for to clarify innocence or guilt in a case?

DNA

What is recidivism?

A person’s relapse into criminal behavior, often after the person has received sanctions or undergoes intervention for a previous crime.

What is the 3-year recidivism rate in NYC?

43%

Was there an existing law that allowed for justice involved persons to apply for their criminal history to be sealed? What was it? Was it an easy process?

The 2017 Sealing Law but it is very burdensome and a long process. Individuals convicted of up to two crimes can have their convictions sealed after a ten year waiting period 

Is the Clean Slate Act accessible to every type of criminal history?

no, only misdemeanor with no sex offense and some felonies 

What are the 3 major tenets of the Innocence Projects’ work?

Restore Freedom, Support Post Incarceration and Transform the system

What does the innocence project’s “transforming the system” look like? What do they describe doing?

They shine a light on factors to consider that lead to a wrongful conviction Identify & share recommended reforms to combat wrongful convictions

What are the key factors that can lead to wrongful conviction

Eyewitness misidentification, misapplication of forensic science, false confessions, unreliable, unregulated jailhouse informants, inadequate defense, official misconduct, coerced pleas, harmful surveillance and investigative techniques,

Is suspect misidentification a significant contributing factor to wrongful conviction?

yes, 63 % of cases involve this

When thinking about how eyewitness misidentification can contribute to wrongful conviction, what are estimator variables?

1.Gaps in witness memory

2.witnesses’ ability to actually clearly see the crime

3, stress or trauma the witness experienced

4.visibility conditions

5.challenged with cross racial identity 

What are the system variables that contribute to wrongful convictions?

Variables that are controlled by
the criminal legal system
⧫ Law enforcement procedures for
eye witnesses
⧫ How lineups & photo arrays are
given

Key concept: The connection between the suspect and the crime may have been,…

over exaggerated OR the limitations of the techniques that were used were underplayed.

What are 4 techniques that the Innocence projects specifically call out as problematic?

Bite Mark Analysis

⧫ Tool Mark Analysis

⧫ Arson Investigation

⧫ Hair Analysis

⧫ Dog Scent Evidence

⧫ Comparative Bullet Analysis

⧫ Shaken Baby Syndrome

Analysis

What is prosecutorial misconduct

This occurs when a prosecutor violates the law or code of ethics while they’re prosecuting a case

⧫ An example is withholding evidence of innocence or favorable evidence (Brady

Violation)

Who was the first person to be exonerated as a result of new DNA findings?

Kirk Bloodworth, e was convicted, in 1984, of the rape of a
convicted in 1984 of the rape of  a 9-year old girl.
⧫ He was 22 at the time and sentenced to death
in Maryland.
⧫ There was no physical evidence linking him.
He was convicted based on eye witnesses.

How are DNA findings advantageous in forensic science?

high accuracy and reliability individualization identification, linking crimes to suspects, exonerating innocents DNA databases and solving coldcases

What is a short tandem repeat

repeat sequences of non-coding dna that are found between genes that code for proteins, they greatly vary between individuals and the number of repeats is inherited

What did James Watson contribute to discovering

double helix structure of dna

What is the name of Watson’s scientific colleague who contributed to his historic discovery

Francis Crick

Did Watson participate in the Human Genome Project?

yes he was a director from 1988 to 1992

Who was the female scientist who worked on X-ray diffraction images of the DNA molecule that was key research in Watson’s later discovery?

Rosalind franklin

Was Watson’s “shady” ethical practices ignored or did he eventually experience justice

they were ignored until he spoke a racist remark in a newspaper and was removed from his chancellors position in a lab and his public image was never the same

What is a key advantage of using SNP versus STR

provides a vastly richer dataset of hundreds of thousands of markers, which expands capabilities to analyze forensic biological evidence to provide investigative leads far beyond those of STR typing. The power of SNPs lies in their stability, genome-wide distribution, and ability to be detected in smaller DNA fragments, making them particularly useful for analyzing degraded forensic samples. This latter feature allows for the recovery of genetic information from evidence that would otherwise yield incomplete or no STR data.

Singles nucleotide polymorphism

SNPs provide hundreds of thousands of markers, are more stable, and can be detected in very small or degraded DNA fragments, allowing useful genetic information to be recovered even when STRs fail.

Can SNP support forensic genotyping

yes by providing information about an individuals ancestry, physical traits and the ability to analyze degraded samples.

Based on article two what can forensic genotyping include the predictions of

ancestry, physical features and sex and age

What are FGGs

forensic genetic genealogy

Combines

• SNP-based DNA profiles

• Genealogical databases

• Family-tree building

• Kinship matching across multiple generations

FGGs help identify unknown individuals and solve cases even when there is no direct STR match or no suspect in CODIS.

Who won the Nobel prize in medicine for the discovery of the double helix structure of DNA?

Watson Crick and Wilkins

What kind of bond do nucleotide base pairs have?

Hydrogen

Who is Erwin Chargaff?

a biochemist from Austria

What was one of Chargaff’s findings that relates to the structure of DNA.

1. A, T. C & G nucleotide bases are NOT found in equal

amounts

2. The number of nucleotide bases varied in different

species but not very much within the same species

3. The amount of A always equaled the number of T bases

& the amount of C always equaled the number of G

Are DNA replication and cell division the exact same thing?

NO, replication happens in the S phase of Cell division and SNA is synthesized in the 5’; to 4’ direction only. cell division occurs after dna replication

When does DNA replication occur during the cell cycle?

s phase of cell division

How does DNA replication support survival of a species?

allows for transfer of genetic info to the next generation

What are 4 ways in which DNA can be damaged?

cellular metabolism, uv light exposure, ionizing radiation. chemical radiation, replication errors, shaken roughly,

What are 3 environmental factors that can impact the integrity (quality) of DNA?

temperature, humidity and contaminats 

What are 3 examples of what DNA samples can be collected from at a crime scene

blood, semen,saliva, urine, feces, hair, teeth, bone, tissue, cells

What is Touch DNA?

DNA samples that are present in very small amounts.
Can be found in bruises, on the skin of a person, on surfaces that came in
contact with the person

Where can touch dna be collected?

masks, hats, gloves, tools, clothes, toothbrush, eyeglases, brush condoms, tape

What is elimination dna

Samples that are collected from relationship partners, sexual partners, first responders, etc. that may have come in contact with victim or crime scene

Why can elimination dna be useful in a criminal investigation

These samples are taken to eliminate them from suspicion

What is the M vac

a piece of equipment that uses we vacuum technology to spray a buffer(made with solutions that help preserve the DNA) on the area DNA is being collected from.

That same buffer is then effectively sucked back up into the device efficiently collecting all

particles.

Why is it an advantageous piece of equipment for a forensic scientist collecting DNA?

Thermal Cyclers for PCR or Mvac 

When was DNA first used during a criminal case?

the 1980s.First case DNA evidence was used in,in England

Colin

Pitchfork

Who first discovered DNA fingerprinting?

alec jeffries

What does the Innocence Project’s work focus on?

Their work primarily focuses on

cases that have DNA as an

option to clarify innocence or

guilt in a case.

True or false: The combination of SNP’s, FGG’s and genealogical databases have significantly supported the advancement of forensic science and the resolution of unsolved violent crimes and unidentified remains

true

True or false: According to article 2, the trends in solved cases from 2018 to 2024 has
increased dramatically.

true

One of the major challenges in working with DNA is only having small amounts available or
degraded samples. What kind of advancements have helped get past this

PCR,STR typing, aDNA, FGG and WGS

What is WGS

whole genome sequencing

What is STR

short tandem repeats

What are the building block molecules of DNA?

Phosphate group, Deoxyribose sugar, nitrogenous bases (ATCG)