Parents pass down remixed versions of their own chromosomes to children. It turns out that said remixing may increase the chances that the DNA of a given child will be subject to mutations in certain locations. The data provided by this study may be helpful for comprehending mutation pace in humans.
The genome consists of long DNA strands of the double helix that code genes with the use of four chemical "letters". In total, about 3 billion base pairs create 23 pairs of chromosomes in nearly every cell there is. Every chromosome can contain hundreds up to thousands of genes.
Geneticist Molly Przeworski of Columbia University - who was not involved in the project - describes the scale of the research as unprecedented, as 150 thousand people were subject to the study. The resources alone will be beneficial for the field of study.
In order to pass down one's genes to their children, parental stem cells become subject to splitting so that it may become possible to create both egg and sperm cells, each having 23 chromosomes - a half of the genetic material of the original germ cell. Still, before the splitting takes place, each chromosome is subject to recombination called "crossing-over", when DNA segments cross over between chromosomes within a pair. The outcome is that one's offspring will not have its chromosomes identical to the ones of their parents.
The data obtained during the research indicate that such crossovers may affect the mutation pace of particular genes.The team discovered that mutations occurred much more frequently near locations related to where crossovers happened. In the DNA sections within approx. 1000 base pairs of where crossovers had occurred mutations were about 50 times more prevalent that in the entire genome. What is more, the farther from such locations a DNA section was, the fewer mutations it contained.