OVERVIEW

The teaching of Genetics provides students with an integrated view of the main aspects of classical and molecular genetics. To follow the process of the path of knowledge in the genetic field, the topics will be treated through the analysis of experimental evidences and their interpretation.

AIMS AND CONTENT

LEARNING OUTCOMES

Acquisition of knowledge about the bases of formal and molecular genetics: processes of transmission, expression and regulation of genetic information; relationships between genotypes and phenotypes; sources of variation of genetic information: mutation, random fertilization, and recombination between homologous chromosomes during meiosis; the genetics of quantitative characters; population genetics.

AIMS AND LEARNING OUTCOMES

The teaching will lead students to understand the rules of inheritance, their molecular bases and their main applications.

Specifically, the student will acquire the knowledge concerning the formal rules of genetic transmission, the structure and function of genes, the mechanisms for repairing damage to genetic material and controlling gene expression and epigenetic phenomena.

The student will have the ability to apply the acquired knowledge to formalize hypotheses on the hereditary transmission of biological characters, to use methodologies for data analysis and to critically evaluate the analysis of experimental data for hypothesis testing.

PREREQUISITES

To deal with the contents of the course, the basic knowledge provided by the Institutions of Mathematics teaching is necessary.

TEACHING METHODS

The teaching consists of lectures, delivered through multimedia presentations.

Students who have valid certification of physical or learning disabilities on file with the University and who wish to discuss possible accommodations or other circumstances regarding lectures, coursework and exams, should speak both with the instructor and with Professor Sara Ferrando (sara.ferrando@unige.it), the Department’s disability liaison.

SYLLABUS/CONTENT

Mendelian genetics: models, factors, and principles of heredity. Monohybrid and dihybrid crosses: Mendel’s laws. Mendel’s results and fundamental rules of probability. Key concepts: genotype and phenotype; genes and alleles; dominance and recessiveness. Monohybrids, dihybrids, polyhybrids. Gamete combinations and phenotypic frequencies in F2. Testcross.

Extensions of Mendel’s laws: complex correlations between genotype and phenotype. Extensions of Mendelian analysis involving single genes: incomplete dominance, codominance, multiple alleles, pleiotropy. Genetic basis of blood groups (ABO, MN, Rh). Extensions of Mendelian analysis involving multiple genes: gene interaction determining a trait, complementary gene action, recessive epistasis, dominant epistasis.

The chromosomal theory of inheritance. Chromosomes contain genetic material. Mitosis and meiosis. Validation of the chromosomal theory. Specific traits are transmitted by specific chromosomes. Genetic determination of sex. Pedigree analysis.

Linkage, recombination, and gene mapping on chromosomes. Morgan’s experiments. Genetic linkage and recombination. Observed and expected recombination frequencies. Crossing-over: physical exchange between chromatids. Multiple crossovers. Poisson distribution. Mapping function. Relationship between crossover frequency and map distance. Mapping: two-point and three-point crosses. Interference. Mapping in haploid organisms: analysis of ordered tetrads in Neurospora crassa; distance between a marker and the centromere.

DNA: the molecule of heredity that carries, replicates, and recombines genetic information. Experiments identifying DNA as genetic material: Griffith (1928), Avery, McLeod and McCarty (1944), Hershey and Chase (1952), Fraenkel-Conrat and Singer (1957). Experimental proof of semiconservative replication (Meselson and Stahl experiment).

Chromosomal mutations: changes in chromosome number and structure. Overview of major syndromes caused by aneuploidies.

Genetic analysis and mapping in bacteria and bacteriophages. The E. coli chromosome; episomes and plasmids; F and F’ factors; Hfr strains. Gene transfer in bacteria: transformation; conjugation; sexduction. Mapping via interrupted conjugation and transformation. Bacteriophages. Transduction (generalized and specialized). Mapping through transduction. Gene mapping in bacteriophages: phage crosses. Complementation test. Benzer’s experiments: analysis of the rII region of phage T4; mapping by deletion.

Sex determination and sex chromosomes. Sexual differentiation and life cycles. Genetic sex determination in humans. Human X and Y chromosomes. PAR regions. Dosage compensation in humans and other mammals. Barr bodies and heterochromatinization. X chromosome inactivation.

Gene mutations. Classification. Spontaneous and induced mutations. Mutation origins: fluctuation test (Luria and Delbrück) and the replica plating method (Lederberg). Mutagenesis tests (Ames test, micronucleus test).

DNA repair: proofreading, mismatch repair, post-replication and SOS repair, photoreactivation, base and nucleotide excision repair.

Epigenetics: DNA methylation. Histone modification. Epigenetic effects of RNA molecules. Epigenetic effects. The epigenome.

Quantitative genetics. Continuous variation. Statistical parameters (mean, variance, covariance). Genetic and environmental variation. Dominance, interaction, and additive effects. Broad-sense and narrow-sense heritability. Estimating heritability through phenotypic correlation among relatives. Selection and response to selection. Increasing the response to selection.

Population genetics. Allele and genotype frequencies. Hardy-Weinberg law and its extensions. Estimating allele frequencies through the Hardy-Weinberg principle. Inbreeding. Evolutionary processes (mutation, migration, genetic drift, natural selection) affecting allele frequency variation. Haplotypes, basics of molecular anthropology, application of Y chromosome and mitochondrial DNA analysis.

RECOMMENDED READING/BIBLIOGRAPHY

- Pierce – Genetica. Ed. Zanichelli – II ed., 2016

- Griffiths et al. Genetica - Principi di analisi formale. Ed. Zanichelli - VII ed., 2021
- Snustad e Simmons -Principi di genetica. EDISES -IV ed., 2010 

Selected presentations, used during the lessons, will be available on AulaWeb at the end of each cycle of lessons dedicated to a topic of the program.

TEACHERS AND EXAM BOARD

LESSONS

LESSONS START

The teaching will take place during the second semester. For the start of lessons and timetable, consult the following link: http://www.distav.unige.it/ccsbio/orario-lezioni.

Class schedule

GENETICS

EXAMS

EXAM DESCRIPTION

The exam consists of an oral test, during which the student will answer questions asked by the teacher on topics related to: 1) Mendelian genetics; 2) molecular basis of the genotype-phenotype association; 3) quantitative and population genetics.

ASSESSMENT METHODS

The final evaluation of the training course will be carried out by oral examination and will take into account both the level of knowledge and the expository and reasoning skills demonstrated in the discussion of the required subjects.

FURTHER INFORMATION

Regular attendance at lessons is strongly recommended.