Humans Have About 100 Broken Genes Each
A newِ analysis ofِ 185 human genomes indicatesِ that everyِ one ofِ us hasِ aboutِ 100 broken genes.
Some ofِ these lost genes causeِ harmful effects, manyِ seem innocuous, andِ some evenِ seem toِ haveِ some benefit.
Currently, thereِ areِ thousands ofِ disease patients whoِ areِ having theirِ genomes sequenced asِ part ofِ studies allِ around theِ world, study researcher Daniel MacArthur, ofِ the Wellcome Trust Sanger Institute inِ the United Kingdom, told LiveScience.
The researchers looked specifically atِ human’s 20,000 protein-coding genes, whichِ areِ genes thatِ direct theِ production ofِ proteins, theِ molecules thatِ doِ most ofِ the work inِ our cells.
Protein-coding genes makeِ up onlyِ aboutِ 1.5 percent ofِ the human genome, theِ rest areِ regulatory elements andِ other unused DNA sequences.
They analyzed 185 human genomes, searching forِ broken genes, defined asِ genes unable toِ makeِ working proteins becauseِ of a mutation (changes toِ theirِ DNA sequence).
They found 1,285 broken genes, or about 100 per person.
The inactive versions ofِ these genes areِ associated withِ manyِ differentِ traits, MacArthur said.
The majority ofِ these mutations seemِ to beِ in nonessential genes, heِ said.
Some ofِ these genes seemِ to beِ on theirِ way outِ ofِ the door: In oneِ such gene, 42 percent ofِ the participants hadِ atِ least oneِ broken copy ofِ it.
Twenty-six ofِ the broken genes identified wereِ previously implicated inِ causing severe diseases (like cystic fibrosis); 21 lookِ likeِ they mightِ play suchِ a disease-causing role (because theyِ comeِ areِ linked toِ critical proteins inِ the body), butِ they haven’tِ beenِ linked toِ illness before.
We alsoِ found severalِ cases ofِ very rare inactivating mutations thatِ areِ known toِ beِ involved inِ very severe diseases likeِ muscular dystrophy, MacArthur said.
In allِ cases theseِ rare mutations wereِ onlyِ foundِ in oneِ copy ofِ a person’s genes, whereasِ theyِ would needِ to beِ present inِ two copies toِ causeِ the disease — soِ these people areِ unaffected ‘carriers’ ofِ these disease mutations.