intro to morphological, biochemical and molecular markers.pdf
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The document discusses genomics, emphasizing the study of entire genomes, genome mapping, and the use of various genetic markers. It explains the advantages and limitations of different types of markers including genetic, morphological, biochemical, and molecular markers, highlighting their roles in mapping and identifying genes. The content also details the characteristics and applications of molecular markers as tools for genetic analysis.
intro to morphological, biochemical and molecular markers.pdf
- 1. GENOMICS
- 2. • The molecular characterization of whole genomes aims to understand the molecular organization and information content of the entire genome and of the products that the genome encodes • Genome: The entire complement of genetic material in a chromosome set. • Genome mapping: To determine the relative positions of, and the distance between genes or different parts of the genetic material in a chromosome set. • Molecular mapping aids in identifying the location of particular markers within the genome.
- 3. Genomics Structural Genomics Functional Genomics Characterizing the physical nature of whole genomes Characterizing the proteome and over all patterns of gene expression
- 4. • A catalog at the nucleotide (and amino acid) sequence levels of all the genes and gene products encoded by the genome will provide the raw material that can serve as sources of insight into everything ,from practical matters of human disease and agricultural genetics to basic biological phenomena such as thos underlying cell physiology, development , behavior , ecology and evolution
- 5. Steps to make genetic map Markers to generate highly saturated map Physical map Sequencing for the whole genome
- 6. Steps to make genetic map Markers to generate highly saturated map Physical map Sequencing for the whole genome
- 9. Morphological markers • physical or structural features of an organism that can be used to identify or classify it. • The 1st genetic maps were based on morphological or phenotypic markers.
- 10. pace of progress was slow The paucity of such markers. Maps were developed from the analysis of multiple crosses. Some markers were of limited value due to epistatic and pleiotropic effects. Mapping a new gene was a laborious time- consuming process.
- 12. Biochemical Markers • Called biomarkers • Have the advantage that many of the relevant genes have multiple alleles. Example : In human : The gene HLA-DRB1 has at least 290 allele and HLA-B has over 400 alleles
- 15. Biochemical Markers Disadvantages Sex limited Age dependent (change with the developmental stage) Influenced by environment it covers less than 10% of the genome Require prior information Low polymerrphism power
- 16. Gene maps are not very comprehensive Because Genes are very useful markers, but they are by no means ideal: • In most eukaryotic genomes the genes are widely spaced out with large gaps between them. • Only a fraction of the total number of genes, exist in allele forms that can be distinguished conveniently.
- 19. Molecular Markers • Reflect heritable differences in homologous DNA sequences among individuals. • These differences result from: Base-pair changes. Rearrangements (translocation and inversion) . Insertions or deletions. Variation in number of tandem repeats .
- 20. ADVANTAGES OF MOLECULAR MARKERS Ubiquitous. Inherited in a Mendelian fashion. High level of polymorphism. Free of environmental variation. Detectable in all tissues at any stage. Revealing variation at a DNA level
- 21. Characteristics Nondestructive assay. Early onset of phenotypic expression Random distribution throughout the genome . Assay can be automated. DNA has long shelf-life . readily exchangeable b/w labs
- 22. DNA markers Hybridization based markers RFLPs Minisatellites Microsatellites PCR-based markers RAPDs MP-PCR AFLPs SSRs SCoT
- 23. Genetic markers Morphological Biochemical Molecular Single locus markers RFLP Microsatellite SNPs Multi locus markers ISSR AFLP SCoT RAPD