BSC ZO- 103 B. Sc. I YEAR GENETICS, TAXONOMY & EVOLUTION DEPARTMENT OF ZOOLOGY SCHOOL OF SCIENCES UTTARAKHAND OPEN UNIVERSITY Board of Studies and Programme Coordinator Board of Studies Prof. B.D.Joshi Prof. H.C.S.Bisht Retd.Prof. Department of Zoology Department of Zoology DSB Campus, Kumaun University, Gurukul Kangri University Nainital Haridwar Prof. H.C.Tiwari Dr.N.N.Pandey Retd. Prof. & Principal Principal Scientist, Department of Zoology, Directorate of Coldwater Fisheries MB Govt.PG College Research (ICAR) Haldwani Nainital. Bhimtal (Nainital). Dr. Shyam S.Kunjwal Department of Zoology School of Sciences, Uttarakhand Open University Programme Coordinator Dr. Shyam S.Kunjwal Department of Zoology School of Sciences, Uttarakhand Open University Haldwani, Nainital Unit writing and Editing Editor Writer Dr.S.N Bahuguna Dr.H.C.S.Bisht Professor & Head Professor Department of Zoology & Biotechnology Department of Zoology HNB Garhwal( A Central University) DSB Campus, Kumaun University, Nainital, P.B.No.70,Srinagar,Garhwal(246174) Uttarakhand (India). Dr.Dharmendra K.Rathor Assistant Professor Department of Zoology Govt. PG College Lohaghat (Uttarakhand) Course Title and Code : Genetics, Taxonomy & Evolution (BS CZO 103 ) ISBN : 978-93-85740-55-8 Copyright : Uttarakhand Open University Edition : 2017 Published By : Uttarakhand Open University, Haldwani, Nainital- 263139 ss BSCZO-103 Genetics, Taxonomy & Evolution DEPARTMENT OF ZOOLOGY SCHOOL OF SCIENCES UTTARAKHAND OPEN UNIVERSITY Phone No. 05946-261122, 261123 Toll free No. 18001804025 Fax No. 05946-264232, E. mail [email protected] htpp://uou.ac.in Contents Course 3: Genetics, Taxonomy & Evolution Course code: BSCZO103 Credit: 3 Unit Block and Unit title Page number number Block 1 Genetics 1-91 1 Mendalism and Elements of heredity : Elements of heredity and variation, 1-31 Mendel’s principles of heredity, linkage (Coupling and repulsion), crossing-over (mechanism, theories and importance). Chromosomal mapping (Three point cross). 2 Chromosomal Mutation : Classification, Translocation, Inversion, Deletion, 32-51 Duplication, Euploidy, Aneuploidy and Polysomy. 3 Genetic interaction : Gene structure and function. 52 -68 4 69-91 Human genetics : Recessive inherited disorder, dominant inherited disorder, inborn errors. BLOCK 2 Taxonomic concept : 92-158 5 92-108 Taxonomy and Systematics: Introduction to taxonomy and its relationship with systematics. Importance and applications of biosystematics. 6 Zoological Nomenclature : International Code of Zoological Nomenclature, 109-125 Bionomial and Trinomial components of classification. 7 Kinds of taxonomic characters and classification : Taxonomic characters: 126=141 Morphological, Embryological, Cytogenetical, Biochemical and Numerical. Components of classification and Linnaean hierarchy. 8 Concepts of Species : Concept of species and speciation and potential modes of 142-158 speciation. Block 3. Evolution 159-230 9 159-169 Origin of life: Special creation theory, theories of spontaneous generation, cosmozoic theory, theory of chemical evolution and spontaneous origin of life at molecular level. 10 170-184 Concept of organic evolution: Concept of organic evolution: evidences from paleontology (types of fossils and determination of age of rocks and fossils), taxonomy, comparative anatomy, comparative embryology, physiology and biochemistry and cytology. 11 185-210 Theory of organic evolution: Theories of organic evolution: Lamarckism, Darwinism, Mutation theory and modern synthetic theory. 12 211-220 Evolutionary concept: Modern evolutionary Concept and details of micro, macro and mega evolution 13 221-230 Zoogeographical relams: Major Zoo-geographical realms and distribution patterns of animals in different zoogeographical realms. Biogeographical regions in India. ZO -103 Genetics, Taxonomy and Evolution Uttarakhand Open University UNIT I: MENDALISM AND ELEMENTS OF HEREDITY Contents 1.1 Objectives 1.2 Introduction 1.3 Elements of heredity and variation 1.3.1 - Mendel's principles of heredity 1.3.2 - Linkage 1.3.3 - Coupling and repulsion 1.4 Crossing over 1.4.1 - Mechanism of crossing over 1.4.2 - Theories of crossing over 1.4.3 - Importance of crossing over 1.5 Chromosomal mapping 1.5.1 - Three point cross 1.6 Summary 1.7 Self-assessment questions 1.8 Terminal Questions Page 1 ZO -103 Genetics, Taxonomy and Evolution Uttarakhand Open University 1.1 Objectives:- Genetics is the study of genes, genetic variation , and heredity in living organisms. It is generally considered as a field of Biology , but intersects frequently with many other Life sciences and is strongly linked with the study of information systems . The father of genetics is “Gregor Johan Mendel ” a late 19 th -century scientist and Augustinian friar . Mendel studied "trait inheritance" patterns in the way traits are handed down from parents to offspring. He observed that organisms ( Pea plants, Pisum Sativum ) inherit traits by way of discrete "units of inheritance." This term, still used today, is a somewhat ambiguous definition of what is referred to as a gene. However, in this chapter you will be able to understand the heredity and variation, Mendel’s laws, linkage, crossing over and chromosomal mapping etc. 1.2 Introduction:- The term Genetics was firstly introduced by “William Bateson” in 1906 . It has been derived from the Greek word Gene - which means "to become " or "to grow into". Therefore, Genetics may be defined as "the science of coming into being" or study of heredity is called Genetics. Genetics is the science of inheritance and variation. Hence, genetics may be redefined as the science that deals with the structure, organization, transmission and function of genes, and the origin of variation in them. However, heredity may be defined "as the transmission of traits from one generation to the following generations". It is the tendency on the part of the offspring to reproduce to characters of the parents. The resemblance between individuals related by descent may be close, but it is never complete. An offspring is never an exact copy of its parents . Variation in heredity is observed in sexually produced offspring but not in asexually produced clones unless a mutation occurs. It is due to variations that each individual is unique in it and can be readily distinguished from another. Heredity and variations which go side by side are the basis of evolution . The branch of science that deals with the facts and laws of heredity and inherited variations is known as genetics. Genetics is the science which tries to explain why living things resemble with their parents, and yet differ from them. Page 2 ZO -103 Genetics, Taxonomy and Evolution Uttarakhand Open University 1.3 Elements of Heredity and Variation:- The Austrian monk “Gregor John Mendel” is considered as the Father of "Modern Genetics". Mendel made experiments on garden pea plants, species of Lathyrus (Pisum sativum ). He started his work in 1856 and continued it up to 1863 . He presented or published the first report of his work in 1865 in the Annual Proceedings of "Brunn Society for the Study of Natural Science". His original paper "Versuche Uber Pflanzenhybriden" (Experiments on plant hybridization) was published in the Proceedings of the Society in 1866 . Mendel's work was, however, ignored at that time. This was perhaps because of the following reasons: 1. He published his work in an obscure Journal. 2. Scientists failed to notice his work because at that time the scientist world was busy in the controversy arisen by Darwin's theory of "Origin of Species". 3. His ideas were ahead of his time as ignorance prevailed in that period about the cytological basis of heredity. Mendel's published work remained unattained for about 34 years . It received attention in 1900 when the same findings were independently rediscovered by three scientists namely Hugo de Vries from Holland, Carl Correns from Germany and Von Tschermak from Austria. Mendel worked how characters are transmitted from one generation to following and how genes act together to control variable traits ( variations ) such as length, height, coat color, flower color etc. They developed the central concept of genetics. According to this concept, heredity is controlled by a large number of genes that are located on the chromosomes. These are called "heredity vehicles". During 1930s beginning was made to apply biochemical an d biophysical methods for the study of chemical nature of the gene. This led to a new branch of genetics "Molecular Biology". This new approach led to the concept that genes are units of "Biological Information". Because of close association and interdependence between genetics and molecular biology the term "Molecular genetics" is now used. It is that branch of science that is concerned with the study of all aspects of the gene. Mendel made Crosses between different varieties of a garden pea . He crossed these varieties which had contrasting traits or characters. In his simpler experiments, he crossed two plants differing in one character only, such a cross was called monohybrid cross and the hybrids thus produced called monohybrids. In more advanced experiments he crossed two plants differing in Page 3 ZO -103 Genetics, Taxonomy and Evolution Uttarakhand Open University two characters. Such a cross was called dihybrid cross and the resultant hybrids were known as dihybrids . 1.3.1 Mendel's Principles of Heredity:- Since ancient times people knew that parental characters were inherited by the offspring, but did not know