Thursday 3 November 2011

DNA profiling 2

DNA profiling 2

Describe the limitations of DNA profiling in relation to the two uses of DNA profiling.

Paternity Test:
The more people tested the lower the statistical probability.

Criminal Investigation:
New profiling technologies can give incorrect results due to cross-contamination of samples.
DNA evidence is easily planted at a crime scene

Other limitations

End of Genetics paper 2

a)     Calculate the difference in consumption of the 6% alcohol solution between the

I)               NPY -/- and NPY +/+ : 3 grams per kilogram weight are consumed per day
II)              NPY – EX and NPY +/+ 2 grams per kilogram weight are consumed per day

b)     NPY -/- consumes more alcohol than NPY +/+ but NPY-EX consumes less than NPY +/+. NPY -/- also consumes more alcohol than NPY-EX. The consumption levels off at a higher concentration for NPY -/- than it does for NPY-EX.
c)     The relationship between NPY levels and alcohol consumption is inversely related.
d)     NPY -/- can regain the reflex fastest, whereas NPY-EX takes the longest. This is because NPY-EX is affected more by alcohol than NPY-/- is.
e)     The hypothesis is not fully supported. There is a small difference in blood levels at 1 hour and 3 hours.
f)      NPY-EX is more affected to alcohol and thus doesn’t prefer it. Unlike NPY -/- which prefers alcohol because it is less sensitive to alcohol and therefore has more of it.
g)      
a.     Homozygous means that there are two identical alleles of the same gene
b.     It has normal levels of NPY
c.      


NPY+
NPY +
NPY -
NPY +/-
NPY +/-
NPY -
NPY +/-
NPY +/-

100%



1.
a) There is a higher percentage of lectin in all GNA varieties in comparison to Con A varieties by about ten fold.

b) Con A 4 because it has the highest percentage of Aphid and Nematode control.

c) It seems that the higher the lectin content the better aphid control however there does not seem to be a relationship with Nematode control.

d) (5500-3800/5000) x 100 = 34%

e) There is a greater effect of the GM potatoes on protozoa because the percentage difference of the mean mass of protozoa is greater than the nematodes. This is the case for both GNA 2#28 and Con A 31. For example, the percentage difference in mass was 63% and 51% for the flagellates and amoebae but for the nematodes it was only 34%. 

Tuesday 1 November 2011

DNA profiling


DNA profiling
      DNA profiling involves the partial sequencing of genomes
  • ·       Profiles tend to focus on areas of satellite of junk DNA which vary significantly between individuals (e.g. the repeated sequence of 16 base pairs on the short arm of chromosome 1)
  • ·       By sequencing a number of sections a unique genetic fingerprint can be created for an individual.
  • ·       Used for: paternity tests and criminal investigations
  • ·       By obtaining DNA profiles from the child, mother and potential fathers, paternity can be established.


Gel electrophoresis
  • ·       The laboratory technique separates fragments of DNA to identify its origin.
  • ·       Restriction enzymes are used to cut the long filaments of DNA into different sized fragments.
  • ·       The DNA fragments are placed into small wells in the gel which are aligned along one end.
  • ·       The gel is exposed to an electric current that is positive on one side and negative on the other.
  • ·       The effect is that the biggest, heaviest and least charged particles do not move easily through the gel so they get stuck very close to the wells they were in at the origin.
  • ·       The smallest and most charged particles pass through the gel to the other side with least difficulty.
  • ·       Medium sized particles are distributed in between.
  • ·       In the end the fragments leave behind a banded pattern of DNA.


Outline the process of DNA profiling (genetic fingerprinting), including ways in which it can be used (6)

  • DNA profiling is often used for criminal investigations or for paternity tests. Firstly, a sample of DNA (often satellite DNA) is required through either hair or from a sample of saliva. The Polymerase chain reaction (PCR) amplifies the DNA and it is an automated process that can produce sufficient DNA in 20 cycles. The DNA is cut using restriction enzymes and these fragments are separated in a process known as electrophoresis. By sequencing a number of sections a unique ‘genetic fingerprint’ can be created for an individual.


2a.
i)  Both the males and females are affected so it’s not sex linked.

ii) It’s likely to be dominant because most of the parents seem to have these symptoms of LDL cholesterol concentration in the blood.

b. III-I= fhfh and III-2 FHfh
ii) 50%

c) a high chance