POPULATION GENETICS AND EVOLUTION
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- Versione italiana
- Academic year
- 2021/2022
- Teacher
- GUIDO BARBUJANI
- Credits
- 6
- Didactic period
- Secondo Semestre
- SSD
- BIO/18
Training objectives
- Training objectives
The goal of the course is to introduce the students to the main concepts and methods of population genetics, so as to be able to understand the genetic bases of evolution and of the maintenance of genetic diversity. The course includes the critical analysis of scientific papers, in order to make the students familiar with the main areas of ongoing research, including human evolution, genetic epidemiology, interactions between cultural and genomic factors in evolution and the study of ancient DNA.
The main notions will be:
• Concepts of population, equilibrium, evolution of genetic systems;
• Factors causing departure from equilibrium and change of allele frequencies;
• Theoretical models of maintenance of genetic polymorphisms;
• Basic knowledge of gene dynamics in populations and of the genetic factors involved in biological evolution.
The main acquired skills will be:
• Ability to formalise hypotheses about the modes and tempos of evolution of genetic traits;
• Ability to use bioinformatic tools to align DNA sequences;
• Ability to query some biological online resources;
• Ability to analyse genetic data by means of biostatistical tools and of the relative software. Prerequisites
- Students will have to be familiar with the following topics, dealt with in the “Genetics” and “Biostatistics”:
• Mechanisms of genetic information transmission, mutation and recombination;
• DNA replication and gene function;
• Analysis of variance, chi-square test; Course programme
- Course programme
• The course includes 48 hours of lectures and activities at the computer.
Genetic polymorphisms and equilibrium populations (6 hours)
DNA polymorphisms. Measures of genetic and genomic diversity. Hardy-Weinberg equilibrium.
Factors causing departure of populations from equilibrium (24 hours)
Positive and negative assortative mating. Equilibrium under inbreeding. Linkage disequilibrium. Mutatione and equilibrium under recurrent mutation. Genetic drift. Gene flow. Admixture. Hierarchical models of structured populations. Wright’s F statistics. Natural selection. Mutation-selection equilibrium. Sexual selection. Theories on maintenance of genetic polymorphisms: Fisher, Wright, Kimura. Molecular clock and neutral theory of molecular evolution.
Coalescent theory and its applications (12 hours)
Bases of the coalescent theory. Tajima’s test. Computer simulation of genetic processes. Approximate Bayesian Computation (ABC)
Applications (6 hours)
Structure of scientific papers. Critical reading of recent papers on the genetic bases of evolution and epidemiology, on the interactions between biological and cultural factors and on ancient DNA. Didactic methods
- Teaching methods
• Class lectures on all topics of the course;
• Computer sessions in which the concepts learned in the classes will be used to solve simple quantitative genetic problems;
• There is the possibility to participate to the weekly meetings of the Genetics group, in which scientific papers are presented and discussed. Learning assessment procedures
- The exam may be a written test, including:
• Multiple-choice questions on all topics in the course;
• Numerical excercises on the effects of equilibrium, inbreeding, genetic drift, gene flow and selection Mendelian segregation ratios, likage, recombination and population genetics;
• Description and interpretation of one or more experiments discussed in the class;
Pocket calculators can be used. The test will last 1 hour.
Alternatively, the tezt may be replaced by the presentation and critical discussion of a scientific paper, chosen in the recent literature and defined with the teacher. Reference texts
- • All the slides can be downloaded from the web
• Main reference text:
J. H. Relethford (2014) Human Populaton genetics. Wiley-Blackwell, 2012.
Other reference texts:
D.L. Hartl (1988) A primer of population genetics, 2nd ed. W.H. Freeman & Co. (New York)
M. Jobling, E. Hollox, M. Hurles, T. Kivisild, C. Tyler-Smith (2014) Human evolutionary genetics. Garland Science (New York)
Rasmus Nielsen, Montgomery Slatkin. An Introduction to Population Genetics. Sinauer Associates, 2013.
Weng Hsiung Li, Molecular evolution, Sinauer Associates, 1997
