Classical Genetics Lecture 1 PDF

CLASSICAL GENETICS U-BT III Kazim Ali Assistant Professor Biotechnology  Course Outline Midterm Final 1. Classical Mendelian 1. Gene interactions; epistasis and...

CLASSICAL GENETICS U-BT III Kazim Ali Assistant Professor Biotechnology  Course Outline Midterm Final 1. Classical Mendelian 1. Gene interactions; epistasis and genetics (2-5/9/24) 3 multiple alleles, ABO blood type Classes alleles and Rh factor alleles in 2. Monohybrid crosses (9- humans 12/9/24) 3 classes 2. Structure of chromosomes; 3. Dihybrid and Trihybrid Organization of genes and ratios (16-26/9/24) 6 genomes classes 3. Nucleic acid function 4. Principle of independent 4. DNA as warehouse of genetic assortment (30/9-3/10/24) information 3 classes 5. Experimental evidence that DNA 5. Probability in Mendelian is genetic material inheritance (7-17/10/24) 3 6. Sex determination; linkage and classes crossing over 6. Dominance, recessiveness, co- dominance, and semi- dominance 6 classes(21- 24/10/24)  Some Imporatnt Points 1. Mode of examination (MCQs based and online) 2. Midterm (October 28, 2024) 3. Assignment and Quiz (TBD) 4. Attendance egor Mendel, Father of Genetics Johann Gregor Mendel (1822–1884) was a lifelong learner, teacher, scientist, and man of faith. As a young adult, he joined the Augustinian Abbey in Brno (Czech Republic). Supported by the monastery, he taught physics, botany, and natural science courses at the Gregor secondary and university levels. In 1856, he Mendel Gregor Mendel's began a decade-long research pursuit involving work in pea led inheritance patterns in honeybees and plants, to our ultimately settling on pea plants as his primary understanding model system. In 1865, Mendel presented the of the results of his experiments with nearly 30,000 foundational pea plants to the local Natural History Society. principles of He demonstrated that traits are transmitted from inheritance. parents to offspring independently of other traits and in dominant and recessive patterns. In 1866, he published his work, Experiments in Plant Hybridization in the proceedings of the Natural Mendel’s studies of peas revealed the laws of inheritance Mendel’s studies of peas revealed the laws of inheritance...which help us understand human diseases such as sickle cell anemia... Mendel’s studies of peas revealed the laws of inheritance...and hemophilia, as well as countless other human diseases that have a genetic contribution. Pedigree of family carrying hemophilia allele Mendel’s studies of peas revealed the laws of inheritance Mendel’s work laid the foundation for the sciences of plant genetics and plant breeding. Distinguished plant breeder Norman Borlaug 1914-2009, Nobel Laureate 1970 Monoecious Pea Plant Crossing Anthers Anther s Stigm a Ovule s Ovary Petals 1 In crossing peas, the anthers of the female parent are first exposed and then cut off to prevent self- Pea Plant fertilization. Crossing Anthers Anther s Stigm a Ovule s Ovary Petals  Pea Plant 2 Crossing Mature pollen is 3 After fertilization, a collected from small cloth bag is tied another flower and around the fertilized deposited on the flower to prevent stray stigma of the female pollen from entering. parent. Flower on female parent Flower on Gregor Mendel's Hypotheses 1. Hereditary determinants are of a particulate nature. Each genetic trait is governed by unit factors, which "hang around" in pairs (or gene pairs) within individual organisms. 2. When two different unit factors governing the same phenotypical trait occur in the same organism, one of the factors is dominant over the other one, which is called the recessive trait. 3. During the formation of gametes the "paired" unit factors separate or segregate randomly so that each gamete receives either one or the other of the two traits, but only one. Gregor Mendel's Hypotheses 4. The union of one gamete from each parent to form a resultant zygote is random with respect to that particular characteristic. 5. During production of gametes, only one of the "pair members" for a given character passes to the gamete. 6. When fertilization occurs, the zygote gets one from each parent, thus restoring the pair. Monohybrid Cross  X Monohybrid Cross Monohybrid Cross Monohybrid Cross Monohybrid Cross  YY Yy yy Homozygous Heterozygous Homozygous DOMINANT recessive  YY Yy yy Homozygous Heterozygous Homozygous DOMINANT recessive  YY Yy yy Homozygous Heterozygous Homozygous DOMINANT recessive  YY yy yy P1 generation y y y 1/ 1/ y 2 2 1/2 Y 1/2 1/ Yy Yy 2 1/ 1/ Y YY 4 4 1/2 YY Yy Y 1/4 Yy 1/ Yy Yy 2 1/ 1/ 1/4 4 4 F1 generation y 1/2 yy yy 1/4 1/  YY yy P1 generation The Principle of Segregation Yy F1 generation Y y 1/ 1/ 2 2 Y Expected ratio of YY : Yy : 1/ yy 2 Yy genotypes is 1 : 2 : 1 Expected ratio of F1 generation y 1/ 2 dominant:recessi ve phenotypes F2 generation is 3 : 1  Testcros Gametes from homozygous s Gametes from homozygous recessive recessive parent parent yy yy y y y y 1/ 1/ 1/ 1/ 2 2 2 2 Gamete Gamete s from Y s from Y Yy 1/ Yy Yy YY 1/ Yy Yy individu 2 1/ 1/ individu 2 1/ 1/ al 4 4 al 4 4 Y y Y Y 1/ yy yy 1/ Yy Yy y 2 1/ 4 1/ 4 Y 2 1/ 4 1/ 4 ALL Heterozygous & Heterozygous Homozygous genotypes recessive genotypes 1:1.