Molecular markers are DNA fragments linked to specific genome locations, crucial for identifying DNA sequences in biotechnology. Key examples include RFLP, AFLP, RAPD, SNP, and VNTR, which aid in genetic diversity measurement, genetic mapping, and forensic analysis. Genetic mapping determines the order and distance of genes on chromosomes based on recombination frequency, providing insights for breeding and evolutionary studies.

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2. Molecular marker is a fragment
of DNA that is associated with a certain
location within the genome. Molecular markers
are used in molecular biology and
biotechnology to identify a particular sequence
of DNA in a pool of unknown DNA.
They may be due to;
 Base pair changes
 Rearrangement
 Insertion or deletion
 Variation in the number of tandem repeats
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3.  It must be polymorphic so that diversity must
be measured.
 It should be clearly distributed through out
the genome.
 It should distinguishes the homologues and
heterologous.
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4.  RFLP(Restriction Fragment length
polymorphism)
 AFLP(Amplified Fragment Length
Polymorphism)
 RAPD(Randem Amplify of Polymorphic DNA)
 SNP(Short Nucleotide Polymorphism)
 VNTR(Variable Number Tandem Repeats)
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5. ```1).RAPD
It doesn’t required sequence information and
involved amplified random DNA fragments.
 It PCR based
 Dominant
 Used in genetic map and plant breeding
2).AFLP
Restrictive enzyme cuts restrictive fragments
of DNA under restriction process.
 Fast
 Inexpensive
 Variable
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6.  VNTR
 A variable number tandem repeat is a location in
a genome where a short nucleotide sequence is
organized as a tandem repeat. These can be
found on many chromosomes, and often show
variations in length (number of repeats) among
individual.
 Use in genetic analysis
 VNTRs have become essential to forensic crime
investigations, via DNA fingerprinting
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7.  Measure of genetic diversity
 Finger printing
 Genotypic selection
 Identification of genotype
 Marker assisted selection
 Long shelf life of the DNA sample
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8.  Genetic mapping is the processes of
determining the order of and relative
distance between genetic markers on a
chromosome.
 It is based on recombination frequency.
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9.  Recombination fraction is the measure of the
distance between two loci.
 Two loci that show 1% recombination are defined
as being 1 centimorgan (cM) apart in a genetic
map.
 1 map unit= 1cM
 Two genes that undergo independent assortment
have recombination frequency of 50 percent and
are located on non homologous chromosome or far
apart on the same chromosome=Unlinked
 Genes with recombination frequency less than 50%
are on the same chromosome= Linked
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10.  The percentage of recombination progeny
produced in a across is called the
recombination frequency.
RecombinatioFrequency:
=no of recombinant progeny ×100
total no of progeny
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11.  The purpose of genetic mapping is to determine the linear
order and distance of separation among the genes that are
linked to each other along the same chromosome.
 They are useful in predicting results of dihybrid and
trihybrid crosses.
 A genetic map can provide plant and animal breeders with
helpful information for improving agriculturally important
strains through selective breeding.
 Useful from evolutionary point of view. A comparison of
genetic maps for different species can improve our
understanding of the evolutionary relationships among
those species.
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12.  Map generated by genetic techniques is rarely
sufficient for directing the sequences phase of a
genome project. This is for two reasons:
 The resolution of genetic map depends on the
number of crossovers that have been scored.
 Genes that are several tens of kb apart may
appear at the same position in the genetic Map.
 Genetic Maps have limited accuracy.
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