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Within eukaryotic cells, DNA is organized into long structures called&nbsp;[https://en.wikipedia.org/wiki/Chromosome chromosomes]. Before typical&nbsp;[https://en.wikipedia.org/wiki/Cell_division cell division], these chromosomes are duplicated in the process of DNA replication, providing a complete set of chromosomes for each daughter cell.&nbsp;[https://en.wikipedia.org/wiki/Eukaryote Eukaryotic organisms]&nbsp;([https://en.wikipedia.org/wiki/Animal animals],&nbsp;[https://en.wikipedia.org/wiki/Plant plants],&nbsp;[https://en.wikipedia.org/wiki/Fungus fungi]&nbsp;and&nbsp;[https://en.wikipedia.org/wiki/Protist protists]) store most of their DNA inside the&nbsp;[https://en.wikipedia.org/wiki/Cell_nucleus cell nucleus]&nbsp;as&nbsp;[https://en.wikipedia.org/wiki/Nuclear_DNA nuclear DNA], and some in the&nbsp;[https://en.wikipedia.org/wiki/Mitochondrion mitochondria]&nbsp;as&nbsp;[https://en.wikipedia.org/wiki/Mitochondrial_DNA mitochondrial DNA]&nbsp;or in&nbsp;[https://en.wikipedia.org/wiki/Chloroplast chloroplasts]&nbsp;as&nbsp;[https://en.wikipedia.org/wiki/Chloroplast_DNA chloroplast DNA].[https://en.wikipedia.org/wiki/DNA#cite_note-5 <sup>[5</sup>]]&nbsp;In contrast,&nbsp;[https://en.wikipedia.org/wiki/Prokaryote prokaryotes]&nbsp;([https://en.wikipedia.org/wiki/Bacteria bacteria]&nbsp;and&nbsp;[https://en.wikipedia.org/wiki/Archaea archaea]) store their DNA only in the&nbsp;[https://en.wikipedia.org/wiki/Cytoplasm cytoplasm], in&nbsp;[https://en.wikipedia.org/wiki/Circular_chromosome circular chromosomes]. Within eukaryotic chromosomes,&nbsp;[https://en.wikipedia.org/wiki/Chromatin chromatin]&nbsp;proteins, such as&nbsp;[https://en.wikipedia.org/wiki/Histone histones], compact and organize DNA. These compacting structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed.<br/> <br/> full text link&nbsp;:&nbsp;[https://en.wikipedia.org/wiki/DNA https://en.wikipedia.org/wiki/DNA]
 
=== RNA ===
'''Ribonucleic acid'''&nbsp;('''RNA''') is a&nbsp;[https://en.wikipedia.org/wiki/Polymer polymeric]&nbsp;molecule that is essential for most biological functions, either by performing the function itself ([https://en.wikipedia.org/wiki/Non-coding_RNA non-coding RNA]) or by forming a template for the production of proteins ([https://en.wikipedia.org/wiki/Messenger_RNA messenger RNA]). RNA and&nbsp;[https://en.wikipedia.org/wiki/Deoxyribonucleic_acid deoxyribonucleic acid]&nbsp;(DNA) are&nbsp;[https://en.wikipedia.org/wiki/Nucleic_acid nucleic acids]. The nucleic acids constitute one of the four major&nbsp;[https://en.wikipedia.org/wiki/Macromolecule macromolecules]&nbsp;essential for all known forms of&nbsp;[https://en.wikipedia.org/wiki/Life life]. RNA is assembled as a chain of&nbsp;[https://en.wikipedia.org/wiki/Nucleotide nucleotides]. Cellular organisms use&nbsp;[https://en.wikipedia.org/wiki/Messenger_RNA messenger RNA]&nbsp;('''''mRNA''''') to convey genetic information (using the&nbsp;[https://en.wikipedia.org/wiki/Nucleobase nitrogenous bases]&nbsp;of&nbsp;[https://en.wikipedia.org/wiki/Guanine guanine],&nbsp;[https://en.wikipedia.org/wiki/Uracil uracil],&nbsp;[https://en.wikipedia.org/wiki/Adenine adenine], and&nbsp;[https://en.wikipedia.org/wiki/Cytosine cytosine], denoted by the letters G, U, A, and C) that directs synthesis of specific proteins. Many&nbsp;[https://en.wikipedia.org/wiki/Virus viruses]&nbsp;encode their genetic information using an RNA&nbsp;[https://en.wikipedia.org/wiki/Genome genome]. Some RNA molecules play an active role within cells by catalyzing biological reactions, controlling&nbsp;[https://en.wikipedia.org/wiki/Gene_expression gene expression], or sensing and communicating responses to cellular signals. One of these active processes is&nbsp;[https://en.wikipedia.org/wiki/Protein_biosynthesis protein synthesis], a universal function in which RNA molecules direct the synthesis of proteins on&nbsp;[https://en.wikipedia.org/wiki/Ribosome ribosomes]. This process uses&nbsp;[https://en.wikipedia.org/wiki/Transfer_RNA transfer RNA]&nbsp;('''''tRNA''''') molecules to deliver&nbsp;[https://en.wikipedia.org/wiki/Amino_acid amino acids]&nbsp;to the&nbsp;[https://en.wikipedia.org/wiki/Ribosome ribosome], where&nbsp;[https://en.wikipedia.org/wiki/Ribosomal_RNA ribosomal RNA]&nbsp;('''''rRNA''''') then links amino acids together to form coded proteins. It has become widely accepted in science[https://en.wikipedia.org/wiki/RNA#cite_note-1 <sup>[1</sup>]]&nbsp;that early in the&nbsp;[https://en.wikipedia.org/wiki/History_of_life_on_Earth history of life on Earth], prior to the evolution of DNA and possibly of protein-based&nbsp;[https://en.wikipedia.org/wiki/Enzyme enzymes]&nbsp;as well, an "[https://en.wikipedia.org/wiki/RNA_world RNA world]" existed in which RNA served as both living organisms' storage method for&nbsp;[https://en.wikipedia.org/wiki/Genetic_information genetic information]—a role fulfilled today by DNA, except in the case of&nbsp;[https://en.wikipedia.org/wiki/RNA_virus RNA viruses]—and potentially performed catalytic functions in cells—a function performed today by protein enzymes, with the notable and important exception of the ribosome, which is a&nbsp;[https://en.wikipedia.org/wiki/Ribozyme ribozyme].<br/> <br/> Full text link&nbsp;:&nbsp;[https://en.wikipedia.org/wiki/RNA https://en.wikipedia.org/wiki/RNA]
=== eQTL ===
<br/> <br/> <br/> <br/> <br/> <br/> <br/> <br/> <br/> &nbsp;[https://biolecture.org/Main_Page Main Page]&nbsp;»&nbsp;[https://biolecture.org/UNIST_Geromics_course UNIST Geromics course]&nbsp;»&nbsp;[https://biolecture.org/Geromics_Course_Students_Folder_2024 Geromics Course Students Folder 2024]&nbsp;»&nbsp;[https://biolecture.org/HyoungJinChoi_2024_Geromics_Course HyoungJinChoi 2024 Geromics Course]&nbsp;»&nbsp;[https://biolecture.org/Summary_class_Geromics_2024_HyoungJinChoi Summary class Geromics 2024 HyoungJinCho]
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