allozymes and isozymes
TRANSCRIPT
OUTLINE Introduction
Allozymes
Isozymes
Use of Allozymes & Isozymes
Significance of Allozymes & Isozymes study, in Ichthyotaxonomy
Allozyme electrophoresis
Advantages & disadvantages
Conclusion
In Ichthyotaxonomy, DNA based molecular marker(Genetic Marker) plays an important role to identify the phylogenic trends of evolution
Now a days it is being replaced by various other methods of
DNA-marker like,
-Nuclear DNA markers(nDNA)
-Mitochondrial DNA markers(mtDNA)
-Restriction fragment length polymorphism (RFLP) etc.
Introduction
It is typical type of DNA sequence
Used to mark a particular or specific location on the chromosomes
It may also called genetic marker
Molecular Marker
Types of Molecular Marker
Allozyme markers
Nuclear DNA markers (nDNA)
Mitochondrial DNA markers (mtDNA)
Restriction fragment length polymorphism (RFLP)
Random amplified polymorphic DNA (RAPD)
Amplified fragment length polymorphism (AFLP)
Tandem repeated DNA (mini and microsatellites)
Single nucleotide polymorphism (SNP)
Expressed sequence tags (ESTs)
Basic functions of all markers Genetic identification of aquaculture stocks
Identify the phylogenetic relationship between the different species of fishes
Monitoring of inbreeding or other changes in the genetic composition of the
stocks
events and genetic drift
Comparisons between hatchery and wild stocks
Isoenzymes & Allozymes
• Isoenzymes & Allozymes were first discovered by R.L.Hunter & Clement Markert in 1957
• Now days the two words i.e. Isoenzymes & Allozymes are usually used interchangeably
• Examples-
Lactate dehydrogenase (LDH) (chr-12) & (chr-15), malate dehydrogenes glucosephosphate, glucokinase etc.
Allozyme It represents the enzymes which is catalyzed by the
different alleles of the same gene
Allozyme
Isozyme/Isoenzyme
• It represent the enzymes from different genes that process or catalyzed the same reaction
• Differs in amino acid sequence
…..then E1 & E2 will be Isoenzymes
E1E2
A + B AB
Functions of Allozymes in fisheries
To study the Genetic Variability of stock
To demonstrate Allozyme electrophoresis
To identify the genetic behavior of smolt age
To study the genetic characterization of the species and stock
To study the genetic drift of the species and stock
Genome mapping
Functions of Allozymes in Ichthyotaxonomy
Individual identification
Mixed Stock Fishery Analysis(MSFA)
To identify the phylogenetic relationship between the different species of fishes
To identify and arrangement of the species and stock on the basis of their genetic affinity
To identify the genetic diversity with in the stock & cultured species
Allozyme electrophoresis
• Allozyme electrophoresis denotes technique for identifying genetic variation at the level of enzyme
• Genetically different forms of an enzyme that are produced by different alleles at locus
• Detected by electrophoresis
• It is a Co-Dominant Mendelian characters
Process of electrophoresis
Extraction , electrophoresis and observation of protein bands are the methods for detection of allozyme variation
Generally starch gel used for staining
40-50 individual can be analyzed per gel
Drawback of this is that only small fraction of enzyme loci
Advantages of Allozymes & Isoenzymes
Co dominant type markers
Easy to use
Easily adjustable from species to species
Low cost
General applicability
Disadvantages of Allozymes & Isoenzymes
Limited number of available Allozyme loci precludes their use in large-scale genome mapping
Heterozygote deficiencies due to null alleles
Reduce the level of detectable variation due to some changes in DNA sequence
Only a small fraction of enzyme loci appear to be allozymically polymorphic
CONCLUSION
• Although, Isoenzyme & Allozyme are not used so much but yet it gives satisfactory result
• It should apply to the genetics of phylogeny as it gives good result
• It has limited use in fisheries sciences rather than other sciences
RFERENCES
• www.google.com/www.wikipedia.com/isoenzymes
• www.google.com/www.wikipedia.com/allozymes
• www.google.com/pdf/file/genetics in fisheries• www.google.com/pdf/file/application of
isoenzymes and allozymes in fisheries• www.google.com/pdf/file/allozyme
electrophoresis in fisheries
