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Genetik
0 memberIf we compare the mtDNA of two individuals, we can figure out when their most recent matrilineal common ancestor lived—using the molecular clock. The mtDNA of all living modern human beings can be traced back to a single female ancestor, a prehistoric mother. She lived around 160,000 years ago, and in the genetics literature she’s referred to as “mitochondrial Eve.” She has a male counterpart, “Y-chromosomal Adam,” to whom the Y chromosomes passed from father to son can be traced. This Adam lived almost 200,000 years before mitochondrial Eve, however, so we can say with certainty that they weren’t a couple.
You have to go back almost 5,000 years into the past to find the last major migration movement that altered the DNA of all Europeans. The DNA of people who came from the Eastern European steppes 5,000 years ago is still one of the three dominant genetic components on the continent today. The other two originate from early hunter-gatherers and from farmers who migrated there from Anatolia. The genetic ratio of these three archaic populations can be quantified through DNA testing in every person who has European roots.
In the time it takes you to read this chapter, the DNA in millions of your cells will undergo chemical changes—in your skin, in your gut, everywhere. Usually these changes are immediately corrected by the body, but not always. When this process goes awry, it’s called a mutation. If mutations appear during the formation of germ cells—that is, in sperm or egg cells—they can be passed on to the next generation. The body has mechanisms to prevent this; as a result, fertilized germ cells with mutations that cause serious illnesses usually die. But smaller mutations often slip through the net, and a genetic change can thus, under certain circumstances, become hereditary.
The human genome consists of 3.3 billion base pairs. In 2003, when the Human Genome Project came to an end, it would have taken more than ten years to unravel the genetic code of a particular individual. Today our laboratory can process a trillion base pairs every day. The throughput of these machines has increased by a factor of 100 million over the past fifteen years: currently, one sequencer can decode an extraordinary 300 human genomes in a single day.
Duygusal İyileşme
Prof. Mansuy: "Eğer genlerimiz harddisk ise epigenetik harddiskteki yazılımdır."
Sayfa 31 - Gün YayıncılıkKitabı okudu
“Kötülüklerinin bütün iyiliklerini gölgede bırakabileceğini sanmam; gökteki kandiller gibidir onun kusurları gece karanlığında daha parlak görünürler. Babadan kalma kusur bunlar daha çok; kendi seçmiş gibi değiştiremezsin onları.”
Sayfa 22 - Türkiye İş Bankası Kültür YayınlarıKitabı okudu
