El Proyecto Genoma Humano

De Wikillerato

En 1990 el Departamento de Energía y el Instituto Nacional de la Salud de los E.E.U.U comenzaron el ambicioso proyecto de identificar los genes que posee el ADN de los humanos. El trabajo se completó en el año 2003, aunque todavía en la actualidad se sigue analizando la gran cantidad de datos que generó. Las primeras impresiones fueron sorprendentes, entre las que podemos destacar:

1. El genoma humano está compuesto por aproximadamente 25.000 genes. Un número muy parecido al del ratón de laboratorio, algo mayor que el de el gusano nematodo (19.000), casi el doble que el de la mosca de la fruta (13.000) y casi cinco veces el de la bacteria E. coli (4.600).

   * The human genome sequence is almost (99.9%) exactly the same in all people.
   * The average gene consists of 3000 bases, but sizes vary greatly, with the largest known human gene being dystrophin at 2.4 million base pairs.
   * Functions are unknown for more than 50% of discovered genes.

   * About 2% of the genome encodes instructions for the synthesis of proteins.
   * Repeat sequences that do not code for proteins make up at least 50% of the human genome. Repeat sequences are thought to have no direct functions, but they shed light on chromosome structure and dynamics. Over time, these repeats reshape the genome by rearranging it, thereby creating entirely new genes or modifying and reshuffling existing genes.
   * The human genome has a much greater portion (50%) of repeat sequences than the mustard weed (11%), the worm (7%), and the fly (3%).
   * Over 40% of the predicted human proteins share similarity with fruit-fly or worm proteins.
   * Genes appear to be concentrated in random areas along the genome, with vast expanses of noncoding DNA between.
   * Chromosome 1 (the largest human chromosome) has the most genes (3168), and the Y chromosome has the fewest (344).
   

Esto ya ha permitido: Particular gene sequences have been associated with numerous diseases and disorders, including breast cancer, muscle disease, deafness, and blindness. Scientists have identified millions of locations where single-base DNA differences occur in humans. This information promises to revolutionize the processes of finding DNA sequences associated with such common diseases as cardiovascular disease, diabetes, arthritis, and cancers.