Corso di laurea in Scienze Biologiche (L-13)

This course contributes to the educational objectives of the Ecological-Environmental area of the Degree in Biological Sciences, providing students with knowledge and application skills on population genetics, highlighting the interactions between basic evolutionary processes (mutation, natural selection, genetic drift, inincrocio , recombination, gene flow) in modeling the genetic structure and evolutionary trajectories of natural populations.

Practical activities will be carried out in the biomolecular laboratory. Students must acquire the ability to collect and organize data related to laboratory activities independently and to interpret and synthesise the results obtained.

KNOWLEDGE AND UNDERSTANDING - At the end of this course the student will have learned the theoretical foundations and some practical methodologies of the biology and genetics of the natural populations. The analysis of the sometimes discordant hypotheses and theories proposed to interpret and explain the population processes will help the students to critically consider the topics dealt with.

APPLYING KNOWLEDGE AND UNDERSTANDING - At the end of this course the student must be able to integrate the knowledge and skills acquired with those derived from other courses (in particular General Zoology, Ecology, Molecular Biology and Genetics). At the end of the lessons and laboratory activities he/she will also demonstrate that they have gained familiarity with some biomolecular methods and with the main tools and equipment used in a biomolecular laboratory. Students must also have acquired rudiments of data processing.

MAKING JUDGMENTS - At the end of this course the student must have acquired the ability to critically discuss the various hypotheses and methodologies of investigation, and to apply them correctly to the various genetic, populatiionist, taxonomic and evolutionary problems.

COMMUNICATION SKILLS - We will try to stimulate the discussion on some appropriate topics. The common reading of passages of emblematic scientific articles will help to develop communication skills. Further incentive will come from the laboratory activities in small groups (up to 2-3 people).

The course will be taught in italian, with slides and supplementary material in Italian and in English. The suggested textbook is also in english.

The course consists of 32 hours of frontal lessons (attendance is non-mandatory) and 14 hours of mandatory laboratory work.

During laboratory activity students wiil obtain and analyse some genetic polymorphisms in human populations.

Attendance of laboratory and practical activities cannot be less than 70% of the scheduled hours.

The exam will consists of an oral examination and will consist in an  in-depth discussion about the main topics of the lectures.

• Lecture Schedule
• Introduction to the course. (2 hours)

Structure and objectives of the course. Procedures for the final examination. Topics of the laboratory activities. Origins of genetics.

• Origins of modern evolutionism and the "mendelian vs. darwinist" controversy. (4 hours)

The Darwinian theory. Mendel's experiments and insights. The rediscovery of Mendel's laws .

• Origins of genetic variation. (8 hours)

Sources of phenotypic variability. Somatic and germline mutations. Classification of mutations. Point, segmental and chromosomal mutations.

Mutations from triplet expansion: examples of Huntington's and Fragile-X syndromes.

Mutations induced by transposable elements. Reciprocal and non-reciprocal recombination. Concerted evolution of gene families. Mechanisms of concerted evolution: gene conversion and unequal crossing-over.

• Dynamics of genes in populations. (10 hours)

The origins of population genetics.

The principle of Hardy-Weinberg equilibrium. Allele frequencies and genotype frequencies. Calculating allele frequencies from genotype frequencies.

Premises of the HW principle.

Class exercises on the Hardy-Weinberg law.

The "modern synthesis". The Fisher's assumptions. The additive genetic variance.

Selection and fitness coefficients. Experimental examples of departures from the HWE.

The eugenics movement. Impossibility of eradication of recessive disadvantageous alleles.

Natural selection and patterns of interaction between alleles in regimes of complete dominance-recessive, co-dominance, over- and under-dominance.

Definition and examples of directional, stabilizing and disruptive selection. Balanced polymorphism.

Definition and examples of frequency-dependent selection.

Genetic variation in nature. "Standing genetic variation" and the principle of genetic assimilation.

Genetic drift. Definition and examples of "founder effect" and "bottleneck effect".

Inbreeding and "effective population size". Non-random mating effects.

Sewall Wright and the "shifting balance theory".

The amount of enzyme polymorphisms in natural populations. The neutral theory of molecular evolution. The molecular clock theory.

• Molecular evolution. (8 hours)

Origin of new genes. Orthology, paralogy and xenology. Formation of gene families by gene duplication . The different fates of duplicated genes. Evolutionary consequences of gene duplication and pseudogenes formation. Neo- and subfuncionalization of duplicated genes. Examples for globin genes, hox genes, genes for opsins.

Internally duplicated genes. The example of AFGPs.

Introduction to Conservation Genetics

Disputes about the evolution of modern humans.

• Laboratory  Schedule

Rules of conduct and safety in the laboratory. Genomic DNA extraction from buccal swabs. Observation of DNA by agarose gel electrophoresis. (4 hours)

Introduction to single- and multi-locus genetic markers. Origin and evolution of Alu elements. Insertional dimorphism in humans. Set-up of PCR reactions for obtaining loci involved in Alu insertional dimorphisms. (3 hours)

Electrophoretic migration of PCR reactions. Observation and comments on the results obtained. (3 hours)

The Hardy-Weinberg law. Scoring of dimorphic bands. Calculating the observed and expected allele and genotype frequencies. Calculating the chi-square values. Final comments on the results obtained. (4 hours)

DNA Barcoding (4 hours)

Zimmer & Emlen - Evolution: Making Sense of Life (2013) Roberts and Company Publishers ISBN 9781936221172

is suggested.