DNA profiling Flashcards
what does non-coding/ VNTR mean
the sequence doesnt code for a protein
wat is it called when some phenotypes have higher reproductive success than others, causing them to increase in frequency in the population
natural selection
what does the PCR process require
a DNA fragment, DNA nucleotides, DNA primers, taq polymerase
what happens in the first step of PCR
the DNA strand is heated so that the strands separate
what happens in the second step of PCR
the temperature is decreased enabling primers to join to complimentary bases
what is the third step of PCR
the temperature is decreased, enabling taq polymerase to complete the complementary strand
what do restriction endonucleases do
cut out sections of repeating, non-coding sequences to isolate a DNA fragments’ VNTRS
what are the three steps to isolate VNTRS
first scientist must collect a DNA fragment, then use PCR to amplify the fragment, then the scientist isolates the VNTR region of the DNA fragment using a restriction endonuclease
how can scientists use the patterns of bands in a DNA sample
to identify relationships between organisms
how can non-coding sequences vary
in their amount of repeats
why is there a wide variation in the patterns of repeated, non-coding sequences
Changes in the number of repeats within non-coding sequences do not have any impact on an organism’s phenotype.
As a result, natural selection does not act on variation in the number of repeats in non-coding sequences.
Individuals with all patterns of repeats pass them on to their offspring and mutation leads to new variations.
what can DNA profiling be used for
to determine the relatedness of animals and plants, to determine the variability within a population
why are non-coding sequences used in DNA profiling
they are almost always unique in individuals
what gel is used in electrophoresis
agarose gel
what is the process of gel electrophoresis
add samples to the wells, apply voltage to the gel, fragments spread down the gel forming bands, transfer the bands to a membrane, add DNA probes with a stain to make the bands easier to see, take a photo
if a DNA fragment is longer will it travel faster or slower?
slower, and a shorter distance therefore
in DNA and RNA fragments what determines their length
the number of bases
what influences the movement of protein molecules down the gel
length and charge
