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WonderScience fact

Your genome, the full set of DNA instructions in your cells, is extremely similar to anyone else's. A common shorthand is that two people match at about 99.9% of comparable DNA positions.

Biology

Science

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The human genome is about 3.2 billion DNA letters long, so even 0.1% amounts to millions of differences. In 2015 the 1000 Genomes Project, which read the DNA of people from 26 populations, found that a typical person differs from the standard reference genome at 4 to 5 million sites. Most are single-letter changes, but longer stretches that are missing, repeated or reversed affect more letters in total, which is why some scientists put the overall match closer to 99.4%. As a species, humans are genetically quite uniform: roughly 85% of variation is found between individuals within the same population rather than between populations. These small differences still matter, shaping traits such as eye colour, how the body handles medicines and the risk of some diseases.

Türkçe oku
Herhangi iki insanın genomu, yani hücrelerdeki DNA talimatlarının tamamı, birbirine son derece benzer. Yaygın bir özete göre iki kişinin DNA'sı, karşılaştırılabilir noktaların yaklaşık %99,9'unda aynıdır.

İnsan genomu yaklaşık 3,2 milyar DNA harfinden oluşur; bu yüzden %0,1'lik bir fark bile milyonlarca harf demektir. 2015'te 26 topluluktan insanların DNA'sını okuyan 1000 Genom Projesi, tipik bir insanın standart referans genomdan 4 ila 5 milyon noktada ayrıldığını buldu. Farkların çoğu tek harflik değişikliklerdir; ama eksik, tekrarlanmış ya da ters dönmüş daha uzun parçalar toplamda daha fazla harfi etkiler. Bu yüzden bazı bilim insanları genel benzerliği %99,4'e yakın hesaplar. İnsan, tür olarak genetik açıdan oldukça tekdüzedir: Çeşitliliğin kabaca %85'i topluluklar arasında değil, aynı topluluktaki bireyler arasında görülür. Bu küçük farklar yine de önemlidir; göz rengi gibi özellikleri, vücudun ilaçları nasıl işlediğini ve bazı hastalıklara yatkınlığı etkiler.

Sources and further reading

Background reading: Human genetic variation
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