Chapter 2: Genome Structure and Gene Expression

The chapter thoroughly investigates epigenetic regulation mechanisms, particularly DNA methylation and histone modifications that control transposon silencing and gene expression patterns. Meiotic processes and their role in genetic recombination are examined alongside polyploidy phenomena, including autopolyploidy and allopolyploidy, and their evolutionary significance in plant genome evolution and speciation. The discussion extends to cytoplasmic inheritance through mitochondrial and plastid genomes, emphasizing endosymbiotic theory and non-Mendelian inheritance patterns such as vegetative segregation. Gene expression regulation receives extensive coverage, from transcriptional control involving RNA polymerase II and promoter architecture to posttranscriptional mechanisms including RNA interference pathways, microRNA function, and small interfering RNA activity. The chapter also addresses posttranslational regulation through protein degradation systems, specifically ubiquitination and proteasome-mediated proteolysis. Modern molecular techniques for studying gene function are presented, including RNA sequencing, quantitative PCR, mutant analysis, and gene fusion approaches. Finally, the content explores practical applications in plant biotechnology, covering Agrobacterium-mediated transformation, genetically modified crop development including golden rice for nutritional enhancement, and the broader societal implications of agricultural biotechnology.