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These tiny mites live on everyone's face Did you know that you carry tiny members of the order of arthropods that eat, sleep, crawl and breed on your face? Just because they cannot be seen with the naked eye does not mean that they do not exist. Scientists found these parasites in everyone who took part in the new study. Parasitic mites of the genus Demodex live inside hair follicles and feed on sebum. On the human face you can find two types of these mites: long \(Demodex folliculorum\) and short \(Demodex brevis\). Megan Thommes from North Carolina State University calls these parasites very cute creatures: They row their eight legs in the oil like oars and consider us their friends. These beings live within each of us, and it is reassuring that they do not cause problems. But are they so harmless? In fact, Demodex can carry bacteria into the human body that cause irritation and redness of the skin. As a result, acne and pimples appear on the face. DNA test results from about thirty people over 18 years of age showed that all of them were carriers of demodex mites. The study was published in the journal PLoS One. A survey of even more people confirmed the scientists' conclusions - these parasitic mites live in the skin of every person. However, they do not cause problems for most people. Scientists don't know how ticks spread among people. They are believed to be passed from mother to child during breastfeeding. The older a person is, the more of these parasites he has. Researchers believe that ticks go out for walks in the dark. Demodex is our long-time roommate. It likely began to spread around the world with people from Africa, says entomologist Michelle Trautwein of North Carolina State University. Researchers hope that Demodex DNA will help them better understand human evolutionary history by tracing the migration routes of ancient people. How these mites came to us is a big mystery that scientists have yet to solve. Interestingly, Demodex mites from China are genetically different from mites from America. The European and Asian lineages split more than 40,000 years ago, and subcutaneous parasites appear to have done the same. If you've read the article this far please like and subscribe - it really helps the channel. Open the link to find thousands of interesting articles: https://lnkd.in/dNyiufB5 \#nikolays_genetics_lessons

The Role of DNA in Genetics and Evolution: A Comprehensive Overview

Hardy Weinberg Formula Explained In population genetics, the Hardy\_Weinberg principle, also known as the Hardy\_Weinberg equilibrium, model, theorem, or law, states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences. These influences include genetic drift, mate choice, assortative mating, natural selection, sexual selection, mutation, gene flow, meiotic drive, genetic hitchhiking, population bottleneck, founder effect and inbreeding. In the simplest case of a single locus with two alleles denoted A and a with frequencies f\(A\) = p and f\(a\) = q, respectively, the expected genotype frequencies under random mating are f\(AA\) = p2 for the AA homozygotes, f\(aa\) = q2 for the aa homozygotes, and f\(Aa\) = 2pq for the heterozygotes. In the absence of selection, mutation, genetic drift, or other forces, allele frequencies p and q are constant between generations, so equilibrium is reached. The principle is named after G. H. Hardy and Wilhelm Weinberg, who first demonstrated it mathematically. Hardy's paper was focused on debunking the view that a dominant allele would automatically tend to increase in frequency \(a view possibly based on a misinterpreted question at a lecture\). Today, tests for Hardy\_Weinberg genotype frequencies are used primarily to test for population stratification and other forms of non-random mating. Problem: In the formula for determining a population's genotype frequencies, the "2" in the term 2pq is necessary because ________. A\) heterozygotes are always being selected for B\) heterozygotes can come about in two ways\* C\) the population is doubling in number D\) the population is diploid Youtube video: https://lnkd.in/dKMvPasE \#nikolays_genetics_lessons

Princeton geneticists led by Joshua Akey have discovered multiple waves of interbreeding between modern humans, Neanderthals, and Denisovans over 200,000 years. Utilizing advanced genetic tools, they mapped gene flow - showing that these ancient groups interacted more than previously believed. Neanderthals may not have gone extinct but instead interbred into modern populations through interbreeding rather than becoming extinct altogether. 𝘊𝘭𝘪𝘤𝘬 𝘩𝘦𝘳𝘦 𝘵𝘰 𝘳𝘦𝘢𝘥 𝘮𝘰𝘳𝘦 👉 https://lnkd.in/gf_QfUHW Princeton University #PrincetonResearch #NeanderthalEvolution #HumanGenetics #Interbreeding #AncientDNA

Population genetics HW problem and solution The Hardy_Weinberg principle, also known as the Hardy_Weinberg equilibrium, model, theorem, or law, states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences. These influences include mate choice, mutation, selection, genetic drift, gene flow and meiotic drive. Because one or more of these influences are typically present in real populations, the Hardy_Weinberg principle describes an ideal condition against which the effects of these influences can be analyzed. In the simplest case of a single locus with two alleles denoted A and a with frequencies f(A) = p and f(a) = q, respectively, the expected genotype frequencies are f(AA) = p2 for the AA homozygotes, f(aa) = q2 for the aa homozygotes, and f(Aa) = 2pq for the heterozygotes. The genotype proportions p2, 2pq, and q2 are called the Hardy_Weinberg proportions. Note that the sum of all genotype frequencies of this case is the binomial expansion of the square of the sum of p and q, and such a sum, as it represents the total of all possibilities, must be equal to 1. Therefore (p + q)2 = p2 + 2pq + q2 = 1. The solution of this equation is q = 1 p. If union of gametes to produce the next generation is random, it can be shown that the new frequency f satisfies \\textstyle f'(\\text{A}) = f(\\text{A}) and \\textstyle f'(\\text{a}) = f(\\text{a}). That is, allele frequencies are constant between generations. This principle was named after G. H. Hardy and Wilhelm Weinberg, who first demonstrated it mathematically. Youtube video: https://lnkd.in/dt7vUZQa #nikolaysgeneticslessons

My new post is about:https://lnkd.in/deJ8ZhSC Contents Russian Journal of Genetics Vol. 60, No. 9, 2024 REVIEWS AND THEORETICAL ARTICLES A Commentary. Another Unsolvable Problem and Axiom of Biology: It Is Impossible to Deduce Cell Properties in an Organism from the Properties of Its Constituent Cells L. G. Kondratyeva, and E. D. Sverdlov p. 1143 abstract GENERAL GENETICS Nematode Caenorhabditis elegans as an Object for Testing the Genotoxicity of Chemical Compounds S. K. Abilev, E. M. Machigov, S. V. Smirnova, and M. V. Marsova p. 1148 abstract MOLECULAR GENETICS Combination of Histological and Transcriptomic Approaches for Annotation of Cell Types in Non-Model Organisms by Example of Spiny Mice Acomys cahirinus N. S. Filatov, A. I. Bilyalov, G. R. Gazizova, A. A. Bilyalova, E. I. Shagimardanova, M. V. Vorontsova, A. P. Kiyasov, O. A. Gusev, and O. S. Kozlova p. 1153 abstract GENETICS OF MICROORGANISMS Novel ToxA Insertion Element in Pyrenophora tritici-repentis N. V. Mironenko, A. S. Orina, and N. M. Kovalenko p. 1161 abstract PLANT GENETICS Polymorphisms in the Transit Peptide of Phytoene Synthase ZmPSY1 Link to the White Color of Grain Endosperm in Maize Inbred Lines D. Kh. Arkhestova, A. D. Khaudov, A. V. Shchennikova, and E. Z. Kochieva p. 1168 abstract Genetic Evaluation of Juniperus communis L. var. oblonga hort. ex Loudon (Cupressaceae) in Caucasus Regions of Russia Based on nSSR Markers E. V. Hantemirova p. 1176 abstract ANIMAL GENETICS Haplotypic Diversity of Leptidea morsei (Fenton, 1882) (Lepidoptera, Pieridae) on the Northwestern Periphery of the Area O. I. Kulakova, D. M. Shadrin, and A. G. Tatarinov p. 1187 abstract Phylogenetic Analysis of Anatolian Blind Mole Rats (Nannospalax ) with Allopatric 2n = 54 Cytotypes T. Kankılıç, İ. Civelek, and B. Köse p. 1194 abstract Genome Survey of Odontamblyopus sp. for Providing a New Basis for Taxonomy and Demographic History D. Kong, S. Ma, Y. Pan, L. Zhao, and N. Song p. 1204 abstract Whole-Genome Resequencing Analysis of Hybrid White Goats to Identify Fertility-Related Genes M. H. Bao, X. M. Sun, J. Xu, and Y. J. Li p. 1214 abstract HUMAN GENETICS Polymorphic Variants of Long Noncoding RNA Genes in the Development of Type 2 Diabetes Mellitus O. V. Kochetova, D. Sh. Avzaletdinova, T. M. Kochetova, T. V. Viktorova, and G. F. Korytina p. 1224 abstract Association of Polymorphic Loci of Long Noncoding RNA Genes (H19, MEG3, MALAT1, LINC00305, LINC00261, LINC02227, and CDKN2B-AS1 ) with Chronic Obstructive Pulmonary Disease G. F. Korytina, L. Z. Akhmadishina, V. A. Markelov, T. R. Nasibullin, Y. G. Aznabaeva, O. V. Kochetova, N. N. Khusnutdinova, A. P. Larkina, N. Sh. Zagidullin, and T. V. Victorova p. 1233 abstract The Change in the Population Structure of the Kursk and Voronezh Guberniya in the First Half of the 20th Century. Malecot’s Isolation by Distance K. N. Sergeeva, S. N. Sokorev, Y. I

In the race in becoming human, pigs come in a close second. Here’s why… There are a number of similarities between humans and pigs. These include various anatomic and physiologic traits, such as organ placement (and often size and function), skin similarities and some disease progression. A pig weighing around 60 kilograms will, for example, resemble a human body in many ways, including fat distribution, cover of hair and ability to attract insects. For this reason, pigs have been used in medical research for over 30 years, and are what’s known as a translational research model. This means that if something works in a pig, it has a higher possibility of working in a human. Comparison of the full DNA sequences of different mammals shows that we are more closely related to mice than we are to pigs. We last shared a common ancestor with pigs about 80 million years ago, compared to about 70 million years ago when we diverged from rodents. A new study has revealed a potential hidden evolutionary link between pigs and primates. Genetic elements called SINES (short interspersed elements) are usually considered to be ‘junk DNA’, left behind by marauding viruses. However, these elements may hold additional clues about our mammalian evolutionary history. In humans, the most common SINE is the Alu transposable element, which is derived from the small cytoplasmic 7SL RNA. The latest research has revealed that 7SL RNA is also the original source for a common swine SINE. Just a fluke? Unlikely, according to researchers, who think that this SINE must have had a common origin. This suggests that there are close parallels between the evolution of this element in pig and primate lines, whereas it died out in the rodents. Some scientists believe that the results are ‘convincing enough to classify the suidae (swine) into a family mainly inhabited by primates’, though the evidence from the entire genome disputes this. The genome is a complex puzzle. Bits of it came from different sources and evolved at different rates. While some pieces may match, you need to look at the entire genome to really understand the full picture. Geneticists are busy analysing all aspects of the human genome, including its previously overlooked SINES. So, if you snort when you laugh or pig out at dinner, don’t fret—you’re still human. Get the entire picture @ https://lnkd.in/ek7nGaDz.

### Summary of the Research on Primate Chromosome Maps #### Key Findings 1. **First Complete Sequences**: - Sequences from five great ape species (chimpanzee, bonobo, gorilla, Bornean and Sumatran orangutans) and siamang gibbon. - Revealed significant variation and rapid evolution in Y chromosomes. 2. **Repetitive DNA**: - 62-66% of X chromosomes and 75-82% of Y chromosomes consist of repetitive DNA sequences. - New DNA sequencing technologies made this study possible. 3. **Evolutionary Insights**: - 90% of ape X chromosomes are similar to human X chromosomes. - Only 14-27% of ape Y chromosomes align with human Y chromosomes, showing fast evolution. 4. **Chromosome Length Variation**: - Example: Sumatran orangutan Y chromosome is twice as long as gibbon’s Y chromosome due to DNA repeats. 5. **Palindromes and Gene Copies**: - DNA palindromes (like "racecar") contain many gene copies, providing backup for important genes. 6. **DNA Satellites**: #### Implications for Human Evolution - These findings help understand human evolution by comparing primate chromosomes. - The dynamic nature of the Y chromosome and its role in fertility and genetic diversity are crucial areas of study. ### Step-by-Step Summary 1. **Research Goal**: - To create complete chromosome sequences for non-human primates and study their evolution. 2. **Methodology**: - Sequenced chromosomes of five great ape species and the siamang gibbon. - Focused on X and Y chromosomes due to their roles in sexual development and fertility. 3. **Findings on DNA Sequences**: - Large portions of these chromosomes are repetitive DNA. - New sequencing technologies allowed these discoveries. 4. **Evolutionary Comparisons**: - Compared ape chromosomes to human chromosomes. - Found significant evolutionary differences, especially in Y chromosomes. 5. **DNA Palindromes**: - Identified gene-containing palindromes on X and Y chromosomes. - These palindromes provide genetic backup, essential for species with only one Y chromosome per cell. 6. **Species-Specific DNA Satellites**: - Found unknown repeating sequences near chromosome ends and centromeres. - Offers new areas for genomic research. 7. **Implications**: - Helps understand human evolution and great ape genome structure. - Provides data for conservation genetics to aid endangered species. ### Practical Takeaways - **For Evolutionary Studies**: Use these chromosome maps to study the rapid evolution and unique genetic structures of Y chromosomes. - **For Conservation Efforts**: Apply this genetic knowledge to protect and understand endangered ape species. - **For Medical Research**: Explore implications for human fertility and genetic diversity based on Y chromosome variations. This research emphasizes the dynamic and rapidly evolving nature of Y chromosomes and provides a new foundation for studying human evolution and primate genetics.

ABO blood group problem and Population genetics Hardy-Weinberg equation The Hardy-Weinberg equation is a mathematical equation that can be used to calculate the genetic variation of a population at equilibrium. In 1908, G. H. Hardy and Wilhelm Weinberg independently described a basic principle of population genetics, which is now named the Hardy-Weinberg equation. The equation is an expression of the principle known as Hardy-Weinberg equilibrium, which states that the amount of genetic variation in a population will remain constant from one generation to the next in the absence of disturbing factors. To explore the Hardy-Weinberg equation, we can examine a simple genetic locus at which there are two alleles, A and a. The Hardy-Weinberg equation is expressed as: p2 + 2pq + q2 = 1 where p is the frequency of the "A" allele and q is the frequency of the "a" allele in the population. In the equation, p2 represents the frequency of the homozygous genotype AA, q2 represents the frequency of the homozygous genotype aa, and 2pq represents the frequency of the heterozygous genotype Aa. In addition, the sum of the allele frequencies for all the alleles at the locus must be 1, so p + q = 1. If the p and q allele frequencies are known, then the frequencies of the three genotypes may be calculated using the Hardy-Weinberg equation. In population genetics studies, the Hardy-Weinberg equation can be used to measure whether the observed genotype frequencies in a population differ from the frequencies predicted by the equation. Youtube video: https://lnkd.in/dVAUrrsR #nikolaysgeneticslessons

Common methods used in human genetics analysis Human genetics Human matings, like those of experimental organisms, show inheritance patterns both of the type discovered by Mendel (autosomal inheritance) and of sex linkage. Because controlled experimental crosses cannot be made with humans, geneticists must resort to scrutinizing records in the hope that informative matings have been made by chance. Such a scrutiny of records of matings is called pedigree analysis. A member of a family who first comes to the attention of a geneticist is called the propositus. Usually the phenotype of the propositus is exceptional in some way (for example, the propositus might be a dwarf). The investigator then traces the history of the phenotype in the propositus back through the history of the family and draws a family tree, or pedigree, by using the standard symbols. Many pairs of contrasting human phenotypes are determined by pairs of alleles. Inheritance patterns in pedigree analysis can reveal such allelic determination, but the clues in the pedigree have to be interpreted differently, depending on whether one of the contrasting phenotypes is a rare disorder or whether both phenotypes of a pair are morphs of a polymorphism. Rare inherited disorders are the domain of medical genetics. Youtube video: https://lnkd.in/dPm8BJq7 #nikolaysgeneticslessons