BMOL1001-Genome Revolution Cheat sheet, Cheat Sheet of Cellular and Molecular Biology

Download BMOL1001-Genome Revolution Cheat sheet and more Cheat Sheet Cellular and Molecular Biology in PDF only on Docsity! Genome Evolution: “Genome evolution is the process by which a genome changes in structure (sequence) over time, through mutation, horizontal gene transfer, and sexual reproduction.” DNA sequence: Non-coding DNA can contain regulatory sequences that regulate the expression of the genes Mutations of DNA sequence Mutations are constantly occurring in an organism's genome and can cause either a negative, positive or no effect at all- still changes the genome TYPES OF MUTATIONS Se i v [easeemensen sammeaenseeesss | SE POINT MUTATION: maps to a single site in the genome, corresponding to a single nucleotide pair or a very small part of a single gene enna enoaoan INVERSION: inverts a segment of a chromosome Fanel8-2(part 5) Molecular Biology of the Cll Ge (© Galan Science 2015) replication- mitosis and meiosis - Errors in DNA recombination- meiosis - Errors in DNA repair - Endogenous/exogenous chemical damage Consequences of mutation in DNA sequence: - Selectively neutral: No change to prospects of cell/organism - Damaging: Eg: disrupt coding sequence for key protein- lead to premature cell/organism death Negative/purifying selection - Change for the better: increase likelihood of reproducing - Accumulating changes overtime- evolution of genome characterised by accumulation of changes - Through mutation and natural selection- organisms evolve: genetic specifications change- allow them to survive more easily- exploit environment and reproduce successfully Comparison of DNA sequence across sequences: - Highly conserved sequence- sequence across 3 different organisms have a lot of similarities- typically critical for functioning (that’s why it needs to retain the sequencing) Example of utility in medical research: Mutations within highly conserved gene sequences can cause motor neuron disease and frontotemporal dementia 4 ways the genetic code can be changed I Causes of ' mutation: - Errors in DELETION: deletes a segment of a chromosome DNA { TRANSLOCATION: breaks off a segment from one chromosome and attaches it to another mutation 1 gene —1 ——=__—_—__> Ole + Fe a gene B organism A ‘) organism B ——- ee organism B with new gene 1) Intragenic mutation 2) Gene duplication 3) DNA segment shuffling 4) Horizontal transfer Intragenic mutation: Existing gene randomly modified in DNA sequence that occurs mainly in the process of DNA replication Duplication: Includes gene duplication, segmental duplication or whole genome duplication Create pairs of initially identical genes within a single cell Rearrangement: DNA segment shuffling- 2 or more existing genes can break and re-join to make a hybrid gene Exon shuffling- two or more exons from different genes are combined together/when exons are duplicated Horizontal (intercellular) transfer: Piece of DNA transferred from the genome of one cell to that of another (even to another species) Different to usual vertical transfer of genetic information from parent to progeny Meiosis: - When each of the parental chromosomes align and cross over- this needs to be exact - _ If not- unequal crossing over which leads to gain/loss of DNA O Exon duplication: one chromosome has an extra exon. The other chromosome loses one (a) Exon duplication ui Parental [ chromosomes l ui Recombinant | chromosomes | Exon 1 Exon 1 Exon 2 Exon 3 Lt Exon? Exon 2 Exon 3 | ocombinaon (unequal crossing over! Exon 2 Exon 3 Exon 3 + Exon? Exon 2 SS — ===