Human Genome - Molecular Organization and Gene Content

Molecular Organization and Gene Content

The human genome is organized into chromosomes (very large linear DNA molecules contained within the cell nucleus) and the small mitochondrial DNA (a comparatively tiny circular DNA molecule). Basic information about these molecules and their gene contents are provided in the following table. (Data source: Ensembl genome browser release 68, July 2012)

Chromosome Length (cm) Base pairs Variations Confirmed proteins Putative proteins Pseudogenes miRNA rRNA snRNA snoRNA Misc ncRNA Links
1 8.5 249,250,621 4,401,091 2,012 31 1,130 134 66 221 145 106 EBI
2 8.3 243,199,373 4,607,702 1,203 50 948 115 40 161 117 93 EBI
3 6.7 198,022,430 3,894,345 1,040 25 719 99 29 138 87 77 EBI
4 6.5 191,154,276 3,673,892 718 39 698 92 24 120 56 71 EBI
5 6.2 180,915,260 3,436,667 849 24 676 83 25 106 61 68 EBI
6 5.8 171,115,067 3,360,890 1,002 39 731 81 26 111 73 67 EBI
7 5.4 159,138,663 3,045,992 866 34 803 90 24 90 76 70 EBI
8 5.0 146,364,022 2,890,692 659 39 568 80 28 86 52 42 EBI
9 4.8 141,213,431 2,581,827 785 15 714 69 19 66 51 55 EBI
10 4.6 135,534,747 2,609,802 745 18 500 64 32 87 56 56 EBI
11 4.6 135,006,516 2,607,254 1,258 48 775 63 24 74 76 53 EBI
12 4.5 133,851,895 2,482,194 1,003 47 582 72 27 106 62 69 EBI
13 3.9 115,169,878 1,814,242 318 8 323 42 16 45 34 36 EBI
14 3.6 107,349,540 1,712,799 601 50 472 92 10 65 97 46 EBI
15 3.5 102,531,392 1,577,346 562 43 473 78 13 63 136 39 EBI
16 3.1 90,354,753 1,747,136 805 65 429 52 32 53 58 34 EBI
17 2.8 81,195,210 1,491,841 1,158 44 300 61 15 80 71 46 EBI
18 2.7 78,077,248 1,448,602 268 20 59 32 13 51 36 25 EBI
19 2.0 59,128,983 1,171,356 1,399 26 181 110 13 29 31 15 EBI
20 2.1 63,025,520 1,206,753 533 13 213 57 15 46 37 34 EBI
21 1.6 48,129,895 787,784 225 8 150 16 5 21 19 8 EBI
22 1.7 51,304,566 745,778 431 21 308 31 5 23 23 23 EBI
X 5.3 155,270,560 2,174,952 815 23 780 128 22 85 64 52 EBI
Y 2.0 59,373,566 286,812 45 8 327 15 7 17 3 2 EBI
mtDNA 0.00054 16,569 929 13 0 0 0 2 0 0 22 EBI

Table 1 (above) summarizes the physical organization and gene content of the human reference genome, with links to the original analysis, as published in the Ensembl database at the European Bioinformatics Institute (EBI) and Wellcome Trust Sanger Institute. Chromosome lengths were calculated by multiplying the number of base pairs by 0.34 nanometers, the distance between base pairs in the DNA double helix. The number of proteins is based on the number of initial precursor mRNA transcripts, and does not include products of alternative pre-mRNA splicing, or modifications to protein structure that occur after translation. The number of variations is a summary of unique DNA sequence changes that have been identified within the sequences analyzed by Ensembl as of July, 2012; that number is expected to increase as further personal genomes are sequenced and examined. In addition to the gene content shown in this table, a large number of non-expressed functional sequences have been identified throughout the human genome (see below). Links open windows to the reference chromosome sequence in the EBI (E), NCBI (N), or UCSC (U) genome browsers.

Read more about this topic:  Human Genome

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