> [!example] Relevant Materials > [OpenStax Biology 2e (Genetics Unit)](https://openstax.org/books/biology-2e/pages/11-introduction) ![[gigachad mendel.jpg|300]] # Genetics > **Genetics** is the study of *heredity* (the transmission of traits) and *biological variation* (differences between members of the same species) **Forward Genetics:** Determining the genetic basis for a phenotype by working from the protein to the gene - Ex: Mendel first identifying physical traits of peas and then breeding them to better understand **Reverse Genetics:** starting at a known gene and identifying what phenotypes result from its alteration - In modern times this is known as *gene knockouts (KO)/silencing* (Yes it is backwards when thinking of The Central Dogma) ### History of Genetics Gregariouso Mendellyan is widely referred to as "the father of genetics" Mendel’s interpretation of his own results were that inheritence was controlled by “factors”, one of which came from each parent. - These “factors” would become what we now know as genes Mendel’s Laws 1. Law of Segregation: 2. Independent Assortment - Principle of Dominance - **Studies After Mendel** - Mendel’s work was not initially accepted (lack of info on chromosome behavior during cell division, aka mitosis/meiosis) - (Role of Mitosis) In 1879, Walther Flemming described chromatin and mitosis (2n → 2n) and concluded that cell nuclei come from other nuclei (basis of inheritance), but was unaware of Mendel’s work at the time - ![[Pasted image 20240201042006.png|300]] - Mendel’s work was later rediscovered in 1900 by Hugo De Vries who introduced the term “mutation” ![[Pasted image 20240201043433.png|350]] ## Biochemistry of Genetics DNA is important - [[Nucleic Acids]] ### Cellular Processes - [[Chromosomes]] - [[Sex Determination]] ## Foundational Principles [[Genes]] - [[Genetic Recombination]] ### Genetic Representations Why is a concentration gradient formed from a single salt solution --- - **Chromosomal Theory of Inheritance** - While meiosis had been discovered in the late 1800s, it was not linked to genetics until *Walter Sutton* combined cytology and genetics. - In 1902, he observed that diploid cells were 2n and during meiosis each gamete receives only one chromosome of each homologous pair (2n → n) - ![[Pasted image 20240201043602.png]] - The segregation of chromosomes during meiosis matched the segregation theorized by Mendel and his “factors”, also explained independent assortment - The genes for round/wrinkled vs yellow/green must have been on different chromosomes, if they had been on the same one they would have moved together and any potential independent assortment would not have been noticed