Principles Of Genetics Lecture Notes PDF

PRINCIPLES OF GENETICS (LECTURE) GENE221 FIRST SEMESTER | A.Y. 2024-2025 | INSTRUCTOR: RAMONA S. RENEGADO DNA — a nuc...

PRINCIPLES OF GENETICS (LECTURE) GENE221 FIRST SEMESTER | A.Y. 2024-2025 | INSTRUCTOR: RAMONA S. RENEGADO DNA — a nucleotide consisting of phosphate, sugar, and CHAPTER 1: OVERVIEW OF GENETICS bases (guanine, adenine, thymine, cytosine); the blueprint of life, as it dictates the cells. it is inside the nucleus. Heredity — the passing of traits and the biological ○ the molecule whose building block sequence similarity between parent and offspring. encodes the information that a cell uses to ○ inheritance of traits can be observed in families. construct a particular protein ○ guanine is paired with cytosine, and adenine is Variation — no individual is alike, hence the variation of paired with thymine. if not paired, permanent every person. error will manifest in the organism; (e.g., down syndrome) this could be the cause of mispairing. Genetics — study of heredity & variation. ○ a life science; studies mechanisms of inheritance Genes — basic unit of inheritance. and the effect of these mechanisms on the ○ composed of DNA functioning of the organism and the species. ○ direct the formation of proteins ○ genes may be behind behaviors and traits. ○ protein is important because it determines ○ plays a central role in the study of biology. individual differences. the difference in proteins brings about differences between individuals Gregor Mendel — the father of genetics; pioneered and species. Mendelian genetics using pea plants ○ constitutes distinct regions on the chromosome ○ Proteomics — a new field of study that Genetics ≠ Genealogy considers the type of proteins; made in a Genealogy, unlike genetics, explores the origin, particular type of cell; e.g., muscle cell requires relationship, histories of families and the line of descent abundant contractile proteins, skin cell contains from ancestors. mostly scaly proteins called keratin. ○ Alleles — different versions of the same gene Mendelian/Transmission genetics — the study of traits in ○ Mutation — a process which results in alleles families; the start of Molecular genetics Chromosome — DNA organized in discrete segments. Population — a group of interbreeding individuals. a large there are 46 of these in an organism, but only true to collection of alleles are distinguished by their frequencies. humans (23 pairs from each parent). ○ a large collection of alleles distinguished by their ○ XY - M, XX - F frequencies (genetic sense) ○ 22 autosomes pairs which are the same in both ○ e.g. Swedish population have a greater sexes, and 1 pair of sex chromosomes: the X and frequency of alleles that specify light hair and the Y. skin than people from a population in Ethiopia ○ each chromosome includes hundreds of (dark hair and skin) different genes ○ consists of DNA & protein Population genetics — applied in healthcare and ○ become double stranded due to DNA forensics. the very basis of evolution which is defined as replication, which happens during [s phase] changing allele frequencies in populations. ○ the Y chromosome determines maleness ○ Karyotype — an individual’s complete set of Pedigree line/chart indicates the structure of a family chromosomes schematically. ○ a person who has half their genes is common Genome — the complete set of genetic information of the with each parent and each sibling and organism. one-quarter with each. grandparent; first ○ includes all of the genes present, and DNA cousins share one-eight of their genes. sequence that do not encode genes ○ there are 3 billion genes in a human genome, LEVELS OF GENETICS but only 1.5 million are encoded ○ includes 1.5% of encoded protein GENE221: Principles of Genetics KATE CLARICE B. LEE | Do not distribute! (Lecture)  PRINCIPLES OF GENETICS (LECTURE) GENE221 FIRST SEMESTER | A.Y. 2024-2025 | INSTRUCTOR: RAMONA S. RENEGADO ○ 28,000-34,000 genes Polygenic traits — influenced by two or more genes ○ the rest are unknown, or are sequences that ○ not influenced by the environment turn protein encoding on and off. Risk assessment — estimates the degree to which a Gene pool — consists of all alleles in a population. particular event or situation endangers a population, individuals do not have a gene pool. which can infer that information from a detailed family history, or results of tests that identify a gene variant or an absent/abnormal protein. Individuals carry 2 alleles of each gene: Genetic risk — the likelihood or probability that an Phenotype — external, visible trait that results in a individual will develop a particular disease or health particular genotype condition based on their genetic makeup. Genotype — combination of alleles; features ○ e.g. a woman’s lifetime absolute risk of breast cancer is one in nine. one woman in every nine Types of cells: will develop breast cancer at some point in their Somatic — body cells, comprise majority of an individual’s lives body ○ can be expressed as a percentage or a decimal — make proteins during development using different subsets of genes Relative risk — compares the likelihood that an individual Germline — sex cells located within testis & ovary which or group with a risk factor, such as family history of a produce gametes disease, will develop a health condition (e.g., cancer) or — have the ability to form both somatic and compared/relative with an individual/group with a similar germline cells background without that risk factor. ○ e.g. consider the probability of developing lung ○ all cells except the RBCs contain all genetic cancer among smokers was 20% and 1% among instructions because they die after 72 days; the non-smokers. smokers would be twenty times as bone marrow produces new RBCs. likely as non-smokers to develop lung cancer ○ cell structure is different from one another because it depends on their functions. they only Empiric risk — obtained by observation and experience of use some of their genes, a process called many families where people have that disorder, rather differentiation. than theoretical principles ○ muscle cells (contractile protein fibers), skin cells ○ e.g. the empiric risk of UK parents having (scaly keratins), and connective tissue cells another child with the same condition as their (elastin proteins) have complete genomes. existing one is: 4%, 3%, 6%, etc. TBA Risk factor — a situation that alters incidence of a disease or trait; threatening. Genetic determinism — an inherited trait is inevitable. ○ something that increases your chances of may be harmful/helpful depending on how we apply it. getting a particular disease ○ idea: “we are our genes”, “it’s in her DNA”, and ○ e.g. smoking increases your chances of “you have a 45% chance of developing cancer” developing cancer. therefore, smoking is a risk instead of “you will get cancer” factor for cancer Applications of Genetics Multifactorial/complex traits — determined by one or more genes Identity — forensics, paternity testing ○ influenced by the environment Health care — prediction of disease, development of treatments, family planning Mendelian traits — inherited traits are determined by one a — crop and animal breeding, genetically modified foods, gene pest management GENE221: Principles of Genetics KATE CLARICE B. LEE | Do not distribute! (Lecture)  PRINCIPLES OF GENETICS (LECTURE) GENE221 FIRST SEMESTER | A.Y. 2024-2025 | INSTRUCTOR: RAMONA S. RENEGADO Bioethics — addresses personal issues that arise in applying medical technology; founded in the 70s ○ addresses concerns that new genetic knowledge raises such as privacy, confidentiality, and discrimination Genomics — considers many genes at a time (in contrast to the emphasis on a single-gene traits that pervaded genetics during the 20th century ○ addresses the more common illnesses influenced by many genes that interact with each other Autosome — a chromosome that does not include a gene that determines sex Dominant — an allele that exerts an effect when present in just one copy Gene expression — a cell’s use of DNA information to manufacture specific proteins Mutation — a change in gene that affects the individual’s health, appearance, or biochemistry Polymorphism — a site in a genome that varies in 1 percent or more of a population Recessive — an allele that exerts a effect only when preset in two copies Sex chromosome — chromosomes that carry genes whose presence or absence determines sex GENE221: Principles of Genetics KATE CLARICE B. LEE | Do not distribute! (Lecture)