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Genome. The genome is all the DNA in a cell. All the DNA on all the chromosomes Includes genes, intergenic sequences, repeats Eukaryotes can have 2-3 genomes Nuclear genome Mitochondrial genome Plastid genome If not specified, “genome” usually refers to the nuclear genome.
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Genome • The genome is all the DNA in a cell. • All the DNA on all the chromosomes • Includes genes, intergenic sequences, repeats • Eukaryotes can have 2-3 genomes • Nuclear genome • Mitochondrial genome • Plastid genome • If not specified, “genome” usually refers to the nuclear genome.
Human genome • Human genome has • 22 autosome pairs + 2 sex chromosomes • 30,000 to 40,000 genes • 3.2 billion base pairs of DNA • About 3% codes for proteins • About 40-50% is repetitive, made by (retro)transposition • What is the function of the remaining 50%? From NCBI web site, photo from T. Ried, Natl Human Genome Research Institute, NIH
Human Genome • mitochondrial genome with 37 genes
Mitochondrial DNA Human mitochondrial DNA (mtDNA) consists ofapproximately 16.5 kb (16,569 bp), 37 genes , closed double stranded circular DNA (Holland and Parsons, 1999). Most of the sequence variation in this DNA is found in 2 hyper-variable segments: hypervariable segment І (HVS-І) and hypervariable segment ІІ (HVSІІ (Holland and Parsons, 1999).
Human Genome Continue (HGP) ……. • Human genome project (HGP) was started in 1990 as first biggest project in biology with a projected time-span of 15 years.
The goals of Human Genome Project • To acquire fundamental information about human genetic make-up to aid for the understanding of human genetics and the role of various genes in health and disease. • To sequence vastly larger nuclear genome (300 Mb) following the publication of small (16.5 kb) mitochondrial DNA (mtDNA) sequence in 1981. • C. Development of appropriate technologies and tools. • D. Genome projects for five model organisms; E.coli, the yeast, the roundworm, the fruit fly and the mouse.
The Outcomes: • By 2003, the genome sequence of 140 other organisms was determined. • Most of the DNA sequencing was performed in five major research centers (one in UK (Welcome Trust) and four in USA)) along with many other (18 in total) countries.
Single Nucleotide Polymorphisms • Single nucleotide polymorphism (SNPs) in the human genome are the change of single nucleotides at a particular loci.
Single Nucleotide Polymorphisms (SNPs) • A single-base sequence variation between individuals at a particular point in the genome called SNPs (pronounced as snip). • SNPs are abundant in human genome and are being used for linkage studies to track genetic diseases. • Individual 1 AGTCAGTCCTAGGA • Individual 2 AGTCAGACCTAGGA
Single Nucleotide Polymorphisms continue......... • On the basis of the number of alleles • in each locus, SNPs are counted as • biallelic polymorphisms, however, • triallelic SNPs are also known to occur • at a very low frequency within the • human genome (Brookes, 1999).
References Human Molecular Genetics, Third Editionby Tom Strachan and Andrew Read Human Molecular Genetics, Third Editionby Tom Strachan and Andrew Read http://www.diffen.com/difference/Animal_Cell_vs_Plant_Cell For Molecular Genetics Glossary http://onlinelibrary.wiley.com/doi/10.1002/0471719188.gloss/pdf