Biology 2581B Lecture Notes - Lecture 15: Micronucleus, Mycobacterium, Genome Size
14 Apr 2016
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Lecture 15 genes and gene expression 2. Methods for mass production of rrna genes: products are so vital! Lsu and ssu rrna genes are intact and repeated (head-to-tail) Euglena nuclear genome: normal linear chromosomes, haploid rrna genes found on a separate circular chromosome that is copied 600 times in the nucleus (breaks the rule of only linear nuclear chromosomes) Lsu gene is fragmented; rna joined by base pairing. Trypanosomes: big, linear nuclear chromosomes with genes and non-coding dna. Chromosomes separated into a few dozen polycistronic units that include many unrelated genes get a few massive transcripts. A few areas of monocistronic units (genes separated by non-coding dna) which encode 5" caps. Trans-splicing: 5" caps break up polycistronic units mature mrna is the individual genes with a 5" cap. Oxytricha (ciliate): 2 different nuclei with 2 different genomes. Thousands of tiny, linear chromosomes containing 1 gene.
