WHAT U MEAN BY DNA FINGERPRINTING EXPLAIN - Biology - Molecular Basis of Inheritance

Question

WHAT U MEAN BY DNA FINGERPRINTING?EXPLAIN

C. Muthu Kumari · Accepted Answer

Dear Student

DNA
fingerprinting is a method for comparing the DNA sequences of any
two individuals Repetitive DNA is
separated from bulk genomic DNA since it appears as a distinct peak
during density gradient centrifugation Satellites are of two types—micro-satellites and mini
satellites, depending upon the base composition, length of segment
and the number of repetitive units
Satellites do
not code for proteins, but have a major role to play in DNA
fingerprinting
Polymorphism is
actually a result of mutation A germ cell mutation (which can pass
on to the next generation through sexual reproduction) gives rise
to polymorphism in populations
In other words,
an inheritable mutation if observed in higher frequencies in a
population is known as polymorphism Polymorphisms arise normally in
non-coding sequences because mutations in non-coding sequences do
not affect an individual’s reproductive
ability
VNTR (variable number of tandem repeats) are satellite DNAs that
show high degree of polymorphism VNTRs are used as probes in DNA
fingerprinting
First of all,
DNA from an individual is isolated and cut with
restriction endonucleases
Fragments are separated according to their size and molecular
weight on gel electrophoresis Fragments separated on
electrophoresis gel are blotted (immobilised) on a synthetic
membrane such as nylon or nitrocellulose Immobilised fragments are
hybridised with a VNTR probe Hybridised DNA fragments can be
detected by autoradiography VNTRs vary in
size from 0 1 to 20 kb Hence, in the autoradiogram, band of
different sizes will be obtained These bands are characteristic for
an individual They are different in each individual, except
identical twins
Hope you find
this useful,
Cheers!!