28429 - Elements of Vegetal Genetics

Learning outcomes

At the end of the course, the student will know the molecular bases of the genetic information, the inheritance of mendelian traits and quantitative traits. The student will also know the main aspects concerning (i) the effects of native and artificially induced (through mutagenesis) genetic variability, (ii) heterosis, (iii) population genetics and (iv) their applications to breeding of ornamental plants.

Course contents

A) Prerequisites

The students attending this course are required to know the basic aspects of mathematics, chemistry and plant biology. Such  knowledge is provided by the courses taught during the first year, first cycle.

B) Teaching Units                

1. Molecular basis of the replication of the genetic information and of its expression (Total of the teaching unit: 2 hours)

Structure of the genetic material; nucleic acids and nucleotides. DNA and its replication. RNA and its synthesis (transcription). Ribosome, transfer and messenger RNA. Genetic code and protein synthesis (translation). Regulation of gene expression. Inducible and constitutively expresssed genes. Mitosis and meiosis. Crossing-over and its consequences for the transmisssion of the genetic information.

Knowledge obtained in the teaching unit 1

·         The student will learn the structure of the genetic material and knows how it can be replicated (DNA) or transcribed (RNA).

·         The student will learn the main aspects concerning the translation of the genetic information and the regulation of gene expression.

2. Inheritance of mendelian traits, linkage and genetic maps (Total of the teaching unit: 2 hours)

Mendel's experiments. Genes and alleles. Homozygosity and heterozygosity. Principle of segregation. Independent segregation. Linkage among genes and recombination. Two-point testcrosses. Chi-square test applied to mendelian genetics. Gene interactions and epistasis.

Knowledge obtained in teaching unit 2

·         The student will learn how the mendelian genetic information is inherited.

·         The student will learn how to interpret segregation ratios and how to interpret such results in statistical fashion (Chi-square test).

3. Inheritance of quantitative traits (Total of the teaching unit: 3 hours)

Phenotypic and genotypic values; environmental effect. Additive and dominance effects. Experiment of Johansen.

Knowledge acquired through teaching unit 3

·         The student will learn the inheritance of quantitative traits, with emphasis on the effects of environmental factors.

·         The students will learn to interpret the experiment of Johansen and how such experiment allowed Johansen to distinguish the effects of the environment from those with a genetic basis.

4. Changes of the genetic material (Total of the teaching unit: 2 hours)

Gene mutation. Base substitutions and their effects; base insertions and deletions. Chromosome mutations (in short). Genome mutations. Polyploidy and its cytological basis. Autopolyploids and allopolyploids. Evolution in plants by polyploidy (with emphasis on the Triticum genus).

Knowledge obtained in the teaching unit 4

·         The student will learn the main changes of the genetic material (mutations) and the consequences of such changes.

·         The student will learn the importance of mutations in the evolutionary processes in plants.

5. Population genetics and basic principles of plant breeding (Total of the teaching unit: 5 hours)

Allele and genotype frequencies. The Hardy-Weinberg equilibrium and its disturbing forces: mutation, selection, migration, genetic drift and assortative mating. Inbreeding and inbreeding coefficient. Inbreeding depression. Heterosis. Basic concepts for the selection of sexually and vegetatively propagated plants.

Knowledge obtained in the teaching unit 5

·         The student will learn the main genetic aspects of populations of cross-pollinated plants.

·         The student will learn the evolution factors shaping allele and genotype frequencies.

·         The student will learn the main genetic aspects causing inbreeding depression and heterosis.

·    The student will learn the basic aspects of breeding procedures used to select better-performing plants.

6. Genetic engineering (Total of the teaching unit: 4 hours)

Molecular markers and their utilization to investigate genetic variabilty in plants and the identification of genes suitable for marker-assisted selection (MAS). Basic concepts of genetic engineering in plants using Agrobacterum tumefaciens. Applications of genetic engineering in plants. Socio-economic issues related to the production and cultivation of genetically modified (GM) plants. Genome editing in plants.

Knowledge obtained in the teaching unit 6

· The student knows the general aspects on the use of molecular markers to analyse genetic variability in plants and enhance their performance.

· The student knows the general aspects concerning the genetic transformation of plants and their cultivation.

7. Practical exercises (Total of the teaching unit: 12 hours)

The following lab activities will allow the student to undersatnd how the use of molecular markers allow to analyse the genetic variability present in natural and experimental populations. In particular, the student will perform the following activities:

• Extraction and purification of genomic DNA from plants
• Analysis of molecular marker profiles to chracterize genetic variability in plantsl
• Assembly of genetic maps and their use to identify mendelian genes.

 

Readings/Bibliography

F. Lorenzetti, S. Ceccarelli, D. Rosellini, F. Veronesi. Genetica agraria - Genetica e biotecnologie applicate all'agricoltura. Patron, Bologna, 2011.

Teaching methods

The lessons will analyze the main problems related to the basis of genetic variability and the inheritance of characters, with an emphasis on traits of agronomic interest. During the first lessons, the prior knowledge and the learning level of the students on the arguments will be verified.

Assessment methods

The course module is part of the Integrated Course Applications of Genetics and Microbiology, along with the following other teaching module: BIOLOGY AND MANAGEMENT OF USEFUL MICROFLORA. Therefore, the evaluation of the course takes into account jointly the level of knowledge and skills acquired by the student in relation to the contents of all of the above two teaching moduless. The knowledge and skills taught in this course are assessed through an oral exam lasting about 20 minutes and encompassing three questions. In particular, two questions are related to the basic aspects developed in the six teaching units in which the course is articulated, while the third question is more general .

Teaching tools

For lectures, overhead projector, PC and projector will be used. For practical exercises, no specific tool is needed.

Office hours

See the website of Roberto Tuberosa