GEN-3020 Lecture Notes - Lecture 10: Ribosomal Rna, Lymnaea, Myoclonic Epilepsy
9 Oct 2016
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Document Summary
The transmission of genetic information to offspring through the cytoplasm rather than through the nucleus is often from one parent and is defined as extranuclear inheritance. Heteroplasmy refers to the present of two or more distinct variant of dna within the cytoplasm of a cell. Organelle heredity - dna contained in mitochondria or chloroplast determines certain phenotypic characteristics of the offspring. Endosymbiotic theory posits that mitochondria and chloroplasts arose independently 2 billion years ago from free-living bacteria. Organelles possessed attributes of aerobic respiration and photosynthesis respectively. Bacteria were engulfed by larger eukaryotic cells. Eukaryotic cells gained oxidative respiration and photosynthesis mtdna, mitochondrial dna, exists in eukaryotes as double-stranded circular. Also susceptible to mutations because of no structural protection from histones, high reactive oxygen species. Highly mutagenic reactive oxygen species (ros) are generated by cell respiration. Merrf - myoclonic epilepsy and ragged red fiber disease. Ancestral mitochondrial genomes: more genes, few introns, little noncoding.
