Genomic organization in Bioinformatics.pptx

Genomic organization in Bioinformatics

1. Genomic Organization The linear arrangement of DNA components and their partition into chromosomes is referred to as a genomic organisation . “Genome organisation” can also refer to the arrangement of DNA sequences inside the nucleus and the three-dimensional structure of chromosomes.

2. Eukaryotic genomes are linear and follow the Watson-Crick Double Helix structural model. They are contained within chromosomes, bundles of DNA and proteins (Histone) known as nucleosomes. The protein-coding genes in eukaryotic genomes are organised in exons and introns, which represent the coding sequence and intervening sequence, respectively, indicating the functionality of the RNA section of the genome.

3. Eukaryotic Genome Configuration The eukaryotic genome configuration consists of protein-coding regions, gene regulatory regions, gene-related sequences, and intergenic DNA or extra genic DNA, which comprises low copy number and moderate or high copy number repetitive sequences.

4. Eukaryotic Genome Organisation Eukaryotic genomes include two characteristics that pose a significant information processing problem. The standard multicellular eukaryotic cell has a substantially larger genome than a prokaryotic cell. Many genes can only be expressed in certain types of cells due to cell specialisation.

5. A huge amount of DNA that does not direct the synthesis of RNA or protein is included in the reported 35,000 genes in the human genome. The eukaryotic DNA is intricately organised. The DNA-protein complex known as chromatin is not only linked to proteins but is also structured at a higher structural level than the DNA-protein complex in prokaryotes. Eukaryotic cells have a significantly higher concentration of DNA in their nuclei than prokaryotic cells.

6. Structure of the Chromatin Chromatin is the intricate structure of DNA and protein that comprises chromosomes and consists of linear unbroken double-stranded DNA. There are two types of chromatin: Euchromatin Heterochromatin

7. Euchromatin :  It is a lightly packed chromatin that is enriched in genes, and is often under active transcription (but not always). Euchromatin contrasts sharply with heterochromatin, which is densely packed and much less available for transcription. The euchromatic region constitutes 92% of the human genome. Heterochromatin:  It is a densely compacted form of DNA or compressed DNA, which comes in multiple variants. These variants fall somewhere between facultative heterochromatin and constitutive heterochromatin. Both are involved in how genes are expressed.

8. The primary proteins that comprise chromatin are called histones and DNA is wrapped around these histone proteins. There are five main histone classes connected to the eukaryotic genome: H1, H2A, H2B, H3 & H4. These basic proteins are positively charged at normal pH levels, making it easier for negatively charged DNA to bind to them.