6.1.3- Manipulating Genomes Flashcards
what is DNA sequencing?
the nucleotide base sequence of an organism’s genetic material is identified and recorded.
what are the 5 types of gene technology?
-DNA profiling/genetic fingerprinting
-genome sequencing
-gene therapy
-genetic engineering
-ethic of genetic manipulation
what are extrons?
the coding region of DNA
what are introns?
the non-coding region of DNA
does everyone have a unique combination of DNA in the chromosomes of their cells?
yes
what is satellite DNA?
the number of repeats of short sequences of DNA that varies between individuals within the introns/telomeres/centromeres
give details on minisatellite DNA?
-no of base pairs= 20-50
-repeats= 50-100
-name= Variable Number Tandem Repeats
give details on microsatellite DNA?
-no of base pairs= 2-4
-repeats= 5-15
-name= short tandem repeats
what is a genetic fingerprint?
a ‘barcode’ on x-ray film, which are unique to everyone
how is a genetic fingerprint produced?
-DNA is cut into fragments using restriction enzymes
-different people produce different fragments of different sizes
-fragments are sorted by size via gel electrophoresis
-DNA probes used to stick only to fragments containing certain sequences, to produce the DNA valid for identification
what are 5 examples of the uses of DNA profiling?
-collaring criminals
-finding fathers
-proving pedigrees
-establishing evolution
-revealing remains
what are restriction enzymes?
enzymes that are produced by bacteria which cut DNA at specific nucleotide sequences/restriction sites to produce DNA fragments.
how many different restriction enzymes are there and how long are they?
-50 different enzymes that all have their own unique restriction site
-usually 6 bp long
what are DNA probes?
short single-stranded pieces of DNA that are complementary to specific sequences in genomes
how long are DNA probes usually?
60 bp long
in genetic fingerprinting, what are DNA probes used for?
they are used to locate DNA fragments containing certain repeated nucleotide sequences
in genetic engineering, what are DNA probes used for?
they are used to locate specific genes for genetic engineering and to confirm the presence/absence of alleles to diagnose genetic disorders.
what can DNA probes be labelled with?
-fluorescent dyes
-32P radioactive isotopes
how can the genetic fingerprint be used to collar criminals?
-dna can be recovered from hair, blood and semen at crime scenes
-if a suspects genetic fingerprint matches that of the DNA at the crime scene, then the evidence points to the suspect as the criminal
how can genetic fingerprints be used to find fathers?
-half of DNA is inherited from mother and other half is from father
-genetic fingerprint contains half the bands present in father’s genetic fingerprint and half the bands present in mother’s genetic fingerprint
how does gel electrophoresis work?
-the DNA fragment is loaded at the negative end of the electrophoresis due to DNA being negatively charged.
-the DNA fragment moves down the gel, the smallest one moving faster and further.
-they move towards the anode (positive end of the electrophoresis)
what is a Polymerase Chain Reaction?
a technique used to amplify DNA
where does the Polymerase Chain Reaction take place?
in vitro= within machines
what does the Polymerase Chain Reaction involve?
1-Heat at 95.C DNA to denature it into single strands, this breaks the hydrogen bonds holding the bases of the two strands
2- Cool to 55.C and add primers, which anneal to complementary DNA sequences at either ends, running in opposite directions
3- Heat to 72.C (optimum temperature) to allow Taq DNA polymerase to attach to primers
4-Taq DNA polymerase copies each strand, using primers as the starting point
5- Two copies of the original strand are made
6- Repeat cycle again
how many DNA copies are made after 30 PCR cycles?
1000 million
what is DNA sequencing?
an automated process which is based on interrupted PCR and electrophoresis.
what are the 5 ingredients to DNA sequencing?
-DNA fragment
-A,C,G,T free nucleotides
-Taq DNA polymerase
-primer sequences
-buffer
what are bioinformatics?
-the development of software and computing tools needed to organise and analyse the enormous quantities of data being generated.
-used to analyse, organise and store biological data
what is computational biology?
-using the data to build theoretical models of biological systems, used to predict what will happen in different circumstances
what are the three different circumstances in which computational biology is used ?
-working out the 3D structure of proteins
-identifying genes linked to specific diseases in a population
-determining the evolutionary relationships between organisms
what are genome-wide comparisons?
the field of genetics that applies DNA sequencing methods and computational biology to analyse the structure and function of genomes (genomics)
what are the steps to DNA sequencing?
what is next generation sequencing/high-throughput sequencing?
working out the base sequence of strands of DNA has become faster, more automated, which gives a high-throughput sequencing
-it is also cheaper
-human genome can be sequenced in days
-fragments run in parellel
what is the human genome project?
an international effort to map the whole human genome.
-contains 25,000 genes which account for only 1.5% of the human genome
-rest of DNA is non-coding DNA
-it was completed in 2003