One of the works of Alexey Kondrashov is called
the Kondrashov Hypothesis or the deterministic mutation hypothesis. This hypothesis explains the benefits of sexual reproduction. Kondrashov argues that because of the slightly deleterious effect of mutations the population will tend to be composed of individuals with a small number of mutations. Because of the recombination effect of the sex on the genotypes the individuals with fewer and more deleterious mutations will be created. Since there is a major selective disadvantage to individuals with more mutations, these individuals die out. Alexey Kondrashov also worked in the field of protein evolution. Kondrashov states that amino acid composition of proteins varies between taxa, so it can evolve. For example, the organism that has more G+C base pairs in the genome will have more amino acids encoded by G+C rich codons. To support this hypothesis Kondrahov et al. compared sets of orthologous proteins from 15 taxa, which represent three domains of life. The amino acids with reducing frequencies was probably among the first incorporated into the genetic codes. Also, all amino acids except Ser, which have an increase in frequency, were probably recruited late. This process also continues to go today. On August 22, 2012, Kondrashov wrote an article in Nature, describing a link between older fathers and a rise in disorders such as autism. The paper attracted a lot of public attention and Kondrashov was interviewed by
The New York Times,
Los Angeles Times,
The Economist and several television networks. The research investigated the number of spontaneous (
de novo) mutations in humans. It showed that a 40-year-old father transmits nearly two and a half times more mutations to his offspring than a 20-year-old father. As the example, a 20-year-old father can transmit nearly 25 random mutations to the offspring. The number of transmitted mutations is rising on two mutations for every more year. So, a 40-year-old father can transmit nearly 65 mutations to the offspring. The exact reason for it is not well understood, but the collecting of sperm of young men and freezing it for the future can be a clever choice. The brain is usually more affected by these mutations, because more genes are expressed in the brain than in any other organ. ==References==