???? Become a Patron: https://patronite.pl/radionaukowe ???? Make a one-time support: https://suppi.pl/radionaukowe ???? Listen on streaming: https://ffm.bio/radionaukowe ???? Subscribe: / @radionaukowe ???? Website: https://radionaukowe.pl ???? Facebook: / radionaukowe ???? Instagram: / radionaukowe ❌ Twitter: / radionaukowe ???? Visit LAMU: / @letniaakademiamlodychumyslow ???? See more: • Radio Naukowe recommends ???? Contact: [email protected] - It could have been an evolutionary crossover - says Prof. Paweł Stankiewicz, a geneticist from Baylor College of Medicine in the USA, on Radio Naukowe. Together with Prof. Anna Gambin, a bioinformatician from the University of Warsaw, is studying the reduction of the number of chromosomes from 48 to 46 – a key factor in the history of our evolution. The reduction caused a definitive reproductive barrier between the evolutionary lines of primates (we cannot have fertile offspring with gorillas), and could also have contributed to intellectual development and a slimmer posture. - The reduction occurred as a result of the fusion of two chromosomes that are still present in primates: chromosome 2A and 2B, as a result of the so-called fusion. Analyzing the location of this fusion in the human genome in different populations, we found that it is the same everywhere. Using bioinformatic and molecular methods, we proved that this event occurred only once in the history of our evolution - explains Prof. Stankiewicz. The scientists proposed a model in which the source of this fundamental change was a single male. The reduction led to 47 chromosomes in him. He then had offspring with many females, who had the classic 48 chromosomes. In the next generation, there were miscarriages or offspring with 48 or 47 chromosomes. Due to cousin interbreeding, in the third and subsequent generations, individuals with 46 chromosomes appeared. Here you can see the diagram: https://molecularcytogenetics.biomedc... - A twinkle in the eye, an athletic figure, they could attract attention... - Prof. Gambin jokes, but only a little, suggesting that individuals with a reduced number of chromosomes could interbreed more willingly. When did this happen? - We fixed a mathematical error that was in the existing method and from the corrected calculations we received a date of approximately 900 thousand years ago - explains Prof. Anna Gambin. The findings of Prof. Gambin and Prof. Stankiewicz were cited in a recent paper in Science. The authors of the paper estimate that approximately 900 thousand years ago. years ago, we were dealing with the beginning of an evolutionary "bottleneck" - there were supposed to be just over 1,200 individuals of our ancestors on Earth, capable of reproducing. And that for 100,000 years. The change could have been permanent thanks to this. - It could have been the so-called founder effect - adds Prof. Stankiewicz. Works: https://pubmed.ncbi.nlm.nih.gov/36008... https://www.science.org/doi/10.1126/s... At the same time, both admit that their dating is not (because it cannot be) 100% certain. The fusion could have occurred earlier. It remains a mystery how many chromosomes, for example, Homo erectus, classified as a member of the Homo genus, had, and lived 2 million years ago. For now, however, there is a lack of suitably preserved genetic material to be able to decide this. In this episode, you'll also hear about whether human evolution is still happening, why we should throw out the term "junk DNA," why gene regulation is so crucial (look at the butterfly and the caterpillar—they both have the same set of genes!), how many thousands of years can go wrong when modeling the past (and how to limit that), and why Americans are eager to work with computer scientists from Poland. 00:00 - Introduction 01:11 - The uniqueness of the Homo Sapiens genome 06:52 - DNA, genomic diseases, and gene regulation 14:12 - When did evolution reduce the number of chromosomes? 27:22 - Did all humans come from one individual? What happened 900,000 years ago? 37:38 - The human population bottleneck and its consequences 43:03 - The next evolutions of man 47:29 - Mathematical models and dating the origin of the human species 53:35 - Cooperation with James Lupski 57:09 - Work at the Texas Medical Center 59:37 - Cooperation with the University of Warsaw 01:01:58 - Further research plans of the guests ???? I recorded the conversation in the RN studio, which I was able to set up thanks to the support at https://patronite.pl/radionaukowe Thank you very much! We have further development plans, if you want to help with them - I encourage you to donate in any amount ???? ???? Radio Naukowe - turn on knowledge! ???? #RadioNaukowe #KarolinaGłowacka????