Judit Kiss, Veronika Suhajdáné Urbán, Hargita Hegyesi

Applied Biology


How much genetic variation exists among humans?

Homo sapiens is a relatively young species and has not had as much time to accumulate genetic variation as have the vast majority of species on earth, most of which predate humans by enormous expanses of time. Nonetheless, there is considerable genetic variation in our species. The human genome comprises about 3 x 109 base pairs of DNA, and the extent of human genetic variation is such that no two humans, save identical twins, ever have been or will be genetically identical. Between any two humans, the amount of genetic variation (biochemical individuality) is about 0.1 percent. This means that about one base pair out of every 1000 will be different between any two individuals. Any two (diploid) people have about 6 x 106 base pairs that are different, an important reason for the development of automated procedures to analyze genetic variation. The most common polymorphisms (or genetic differences) in the human genome are single basepair differences. Scientists call these differences SNPs, for single-nucleotide polymorphisms. When two different haploid genomes are compared, SNPs occur, on average, about every 1000 bases. Other types of polymorphisms (or example, differences in copy number (CNVs), insertions, deletions, duplications, and rearrangements) also occur, but much less frequently. Notwithstanding the genetic differences between individuals, all humans have a great deal of their genetic information in common. These similarities help define us as a species. Furthermore, genetic variation around the world is distributed in a rather continuous manner; there are no sharp, discontinuous boundaries between human population groups. In fact, research results consistently demonstrate that about 85 percent of all human genetic variation exists within human populations, whereas about only 15 percent of variation exists between populations.

Applied Biology

Tartalomjegyzék


Kiadó: Akadémiai Kiadó

Online megjelenés éve: 2020

ISBN: 978 963 454 526 2

Hivatkozás: https://mersz.hu/hegyesi-kiss-suhajdane-applied-biology//

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