BIOCHEMICAL MARKERS
Animals are selected based on biochemical properties. e.g, Hb, AMYLASE, BLOOD GROUPS, etc.
Molecular Marker/DNA Marker
Molecular or genetic marker is a gene or DNA sequence with a known location on a chromosome and is
associated with a particular trait of interest.
It can be described as a variation (which may arise from mutation or alteration in genomic loci) that is
observable. A genetic marker may be a short DNA sequence, such as a single-base-pair change (single-
nucleotide polymorphism, SNP), or a long one, such as minisatellites. Molecular markers are used in
molecular biology and biotechnology to identify a specific DNA sequence within a pool of unknown DNA.
DNA-based / molecular
To avoid problems specific to morphological markers, DNA-based markers have been developed. A unique
DNA sequence near the gene or locus of interest can be identified by a range of molecular techniques. Three
common technologies used as molecular markers are: RFLP, SSR (microsatellites), and SNP.
ADVANTAGES
• Highly polymorphic.
• Simple inheritance.
• Abundantly occur throughout the genome.
• Easy and fast to detect.
• Minimum pleiotropic effect.
• Detection is independent of the organism's developmental stage.
Types of Molecular Markers
1
, Some commonly used types of genetic markers are:
▪ RFLP (Restriction Fragment Length Polymorphism)
▪ SSLP (Simple Sequence Length Polymorphism)
▪ AFLP (Amplified Fragment Length Polymorphism)
▪ RAPD (Random amplification of polymorphic DNA)
▪ VNTR (Variable Number Tandem Repeat) / SSR (Single Sequence Repeat) / STR (Short Tandem
Repeat) - microsatellite, minisatellite, and DNA fingerprinting
▪ SNP (Single Nucleotide Polymorphism)
▪ SFP (Single Feature Polymorphism)
▪ DArT (Diversity Arrays Technology)
Application of Molecular Marker
I. Genetic markers can be used to examine the relationship between production, reproduction, and
inherited disease and its genetic cause (for example, a specific mutation of a gene that leads to a
faulty protein).
II. Genetic markers are used to assess genetic distance and relationships between individuals or
populations.
III. Genetic variation and population structure study in natural populations.
IV. Assessment of demographic bottleneck in natural population.
V. Molecular genetic markers were used to address the issues of natural transmission, evolutionary
genetics, interspecies variability, maternal lineage, and breed of origin, among others.
VI. Genetic markers have been valuable tools in understanding how livestock respond to both natural
and artificial selection, shedding light on the changes in their genetic makeup. When we observe
different alleles caused by distorted segregation at genetic markers, it highlights differences between
livestock that have been selected and those that haven't, helping us better understand selection and its
impact.
VII. Genetic markers also help in genetic engineering because they can be used to produce functioning
proteins that replace defective ones.
Restriction Endonuclease/ Molecular Scissors
A restriction enzyme (or restriction endonuclease) is an enzyme that recognizes specific sequences in
DNA and then cuts the DNA to produce fragments, called restriction fragments.
− Restriction enzyme cuts DNA at or near specific recognition nucleotide sequences known as restriction
sites. To cut DNA, all restriction enzymes make two incisions through each sugar-phosphate backbone
(i.e., each strand) of the DNA double helix.
− Restriction enzymes are isolated from bacteria and archaea. Over 3,000 restriction enzymes have been
studied in detail, and more than 600 are available commercially.
− These enzymes are routinely used for DNA modification in laboratories and are a vital tool in
molecular cloning.
− Restriction enzymes play a very important role in the construction of recombinant DNA molecules, as
is done in gene cloning experiments, gene expression, and population genetic studies.
2
Animals are selected based on biochemical properties. e.g, Hb, AMYLASE, BLOOD GROUPS, etc.
Molecular Marker/DNA Marker
Molecular or genetic marker is a gene or DNA sequence with a known location on a chromosome and is
associated with a particular trait of interest.
It can be described as a variation (which may arise from mutation or alteration in genomic loci) that is
observable. A genetic marker may be a short DNA sequence, such as a single-base-pair change (single-
nucleotide polymorphism, SNP), or a long one, such as minisatellites. Molecular markers are used in
molecular biology and biotechnology to identify a specific DNA sequence within a pool of unknown DNA.
DNA-based / molecular
To avoid problems specific to morphological markers, DNA-based markers have been developed. A unique
DNA sequence near the gene or locus of interest can be identified by a range of molecular techniques. Three
common technologies used as molecular markers are: RFLP, SSR (microsatellites), and SNP.
ADVANTAGES
• Highly polymorphic.
• Simple inheritance.
• Abundantly occur throughout the genome.
• Easy and fast to detect.
• Minimum pleiotropic effect.
• Detection is independent of the organism's developmental stage.
Types of Molecular Markers
1
, Some commonly used types of genetic markers are:
▪ RFLP (Restriction Fragment Length Polymorphism)
▪ SSLP (Simple Sequence Length Polymorphism)
▪ AFLP (Amplified Fragment Length Polymorphism)
▪ RAPD (Random amplification of polymorphic DNA)
▪ VNTR (Variable Number Tandem Repeat) / SSR (Single Sequence Repeat) / STR (Short Tandem
Repeat) - microsatellite, minisatellite, and DNA fingerprinting
▪ SNP (Single Nucleotide Polymorphism)
▪ SFP (Single Feature Polymorphism)
▪ DArT (Diversity Arrays Technology)
Application of Molecular Marker
I. Genetic markers can be used to examine the relationship between production, reproduction, and
inherited disease and its genetic cause (for example, a specific mutation of a gene that leads to a
faulty protein).
II. Genetic markers are used to assess genetic distance and relationships between individuals or
populations.
III. Genetic variation and population structure study in natural populations.
IV. Assessment of demographic bottleneck in natural population.
V. Molecular genetic markers were used to address the issues of natural transmission, evolutionary
genetics, interspecies variability, maternal lineage, and breed of origin, among others.
VI. Genetic markers have been valuable tools in understanding how livestock respond to both natural
and artificial selection, shedding light on the changes in their genetic makeup. When we observe
different alleles caused by distorted segregation at genetic markers, it highlights differences between
livestock that have been selected and those that haven't, helping us better understand selection and its
impact.
VII. Genetic markers also help in genetic engineering because they can be used to produce functioning
proteins that replace defective ones.
Restriction Endonuclease/ Molecular Scissors
A restriction enzyme (or restriction endonuclease) is an enzyme that recognizes specific sequences in
DNA and then cuts the DNA to produce fragments, called restriction fragments.
− Restriction enzyme cuts DNA at or near specific recognition nucleotide sequences known as restriction
sites. To cut DNA, all restriction enzymes make two incisions through each sugar-phosphate backbone
(i.e., each strand) of the DNA double helix.
− Restriction enzymes are isolated from bacteria and archaea. Over 3,000 restriction enzymes have been
studied in detail, and more than 600 are available commercially.
− These enzymes are routinely used for DNA modification in laboratories and are a vital tool in
molecular cloning.
− Restriction enzymes play a very important role in the construction of recombinant DNA molecules, as
is done in gene cloning experiments, gene expression, and population genetic studies.
2
