Download DNA Review Packet - Ms. Bloedorn`s Class

DNA Review Packet
S
Q14. What was the dominant
DNA typing procedure in the
US until the mid-1990s?
S RFLP analysis
Q15. What is a short tandem repeat
(STR)? Why are STRs so attractive
to forensic scientists?
S A STR is a region of a DNA molecule that contains
short segments consisting of three to seven repeating
base pairs.
S STRs are attractive to FS because hundreds of different
types of STRs are found in human genes. The more
STRs one can characterize, the smaller the percentage
of the population from which these STRs can come,
thus making it easier to positively link biological
evidence with a particular suspect. Also, STRs can be
replicated by PCR.
Q. 16 How does the number of STRs
characterized relate to the frequency of
occurrence of the analyzed sample in the
general population?
S The greater the number of STRs characterized, the
smaller the frequency of occurrence of the analyzed
sample in the general population.
Q 18. What gene is often used to determine the sex
of a DNA contributor? What characteristic of the
gene allows forensic scientists to make this
determination?
S Oops! You can skip this one, too.
S You know what? You deserve a sticker. See Ms.
Bloedorn and keep up the good work. 
Q19. List two differences between
nuclear DNA and mitochondrial
DNA.
S Nuclear DNA is found in the nucleus and inherited
from both parents.
S Mitochondrial DNA is found outside the nucleus in the
mitochondria and inherited from the mother.
Q20. Name one advantage and three
disadvantages of mtDNA analysis
compared to nuclear DNA profiling.
S One advantage is it is significantly more sensitive than
nuclear DNA profiling.
S Disadvantages:
S More time consuming
S More costly
S Has far less discriminating power than STRs
Q21. What is CODIS? How is
CODIS useful to forensic scientists?
S CODIS (Combined DNA Index System) is a computer
software program developed by the FBI that maintains
local, state, and national databases of DNA profiles
from convicted offenders, unsolved- crime scene
evidence, and profiles of missing people.
S CODIS is useful to FS because it allows them to
compare DNA types recovered from crime scene
evidence to those of convicted sex offenders and
criminals.
Q23. What type of gloves should an evidence
collector wear when handling biological
evidence? Name two reasons he or she should
wear this type of glove.
S An evidence collector should wear latex gloves
because:
S 1) Biological evidence should be assumed to be
infectious.
S 2) It reduces the possibility of contamination.
Q24. What type of packaging should not be
used for biological evidence? Why? What
should be used?
S Plastic or air-tight packaging should not be used for
biological evidence, because the moisture could let
bacteria and fungi grow, which can destroy DNA.
S Evidence should be packaged in a paper bag or well-
ventilated box.
Q25. How should packages containing
biological evidence be stored until they
are delivered to a lab?
S They should be refrigerated or stored in a cool location
until they can be delivered.
Q27. Name and describe the least
intrusive method for obtaining a
DNA standard/reference.
S A buccal swab (a swab of the inside of a cheek) is the
least intrusive method for obtaining a DNA standard.
Q29. List the sequence of
bases…
S GCTTAGCGTTAGCTGGAC
Q30
S Test for Y-STRs, following the same procedure as any
other STR test.