Population genetics

Course unit

title

Scientific direction

Scientific code

Faculty

Department (s)

Population genetics

Biology N 010

Life Sciences Center

Institute of Life Sciences

Mode of studies

Number of credits

Mode of studies

Number of credits

Life Lectures

0

Consultations

1

Self-studies

7

Seminars

0

Aims of course

1.     To get acquainted with Ecological Genetics as a field of biological science, its main concepts, and problems.

2.     To acquire knowledge in this field of science that could be applied in original research and interpretation of their results.

Main topics

The populations and ecological genetics as a branch of biological science: task and basic concepts. Fragmentation of the species into populations and the significance of this fragmentation. Genetic variation, its biological levels and extent in natural populations. Genetic markers used to study genetic variation. Advantages and disadvantages of different types of genetic markers. The Hardy-Weinberg model and its uses: tests for departure from Hardy-Weinberg equilibrium. The major factors of population evolution. Non-random mating and its genetic consequences; inbreeding depression. Mutations as ultimate source of genetic variation; the concept of mutation frequency. Migration and its impact on genetic variation within and among subpopulations. Introgression and its consequences for endangered species. The island model as simplest model of gene flow. Genetic drift and its impact on genetic variation within and among subpopulations. Experimental evidence of genetic drift. Comparison of the effects of gene flow and genetic drift on genetic variation within and among subpopulations. F-statistics; calculation of F-statistics, and information provided by estimates. Genetic distance as a measure of genetic differentiation of populations. Effective population size, its significance, and methods of calculation. The bottleneck and founder stages and their effects on the genetic structure of the population. Species surviving the bottleneck. The comparison of effects of genetic drift and inbreeding on the frequency of genotypes and their action on phenotypes. Natural selection on genotypes, its main forms, and effects on the genetic structure of the population. The concepts of absolute, relative, and mean fitness. Directional selection, its causes, and effects on genetic variability. Effect of fitness on Hardy-Weinberg equilibrium, and allele frequencies. Frequency dynamics of the advantageous allele depending on its degree of dominance, and possible types of equilibrium. Haldane’s sieve phenomenon. Calculation of the effect of natural selection on detrimental recessive and favourable dominant allele frequencies.  Stabilizing selection and its genetic consequences. Disruptive selection and its genetic consequences. Balancing selection due to heterozygote advantage, and its effect on population genetic variability. Calculation of equilibrium (optimal) allele frequencies in the presence of heterozygous advantage. A comparison of heterozygous advantage and heterosis phenomena. Possible effects of heterozygous frequency on population suitability. Genotype frequency dependent selection. A comparison of the effects of four evolutionary factors on genetic variation within and among populations. Interactions between the four evolutionary forces (mutations, migration, genetic drift, and selection), and consequences of interactions on genetic variation of populations. The indirect method based on drift-migration equilibrium for measuring gene flow. S. Wright’s shifting balance theory – one of the models of population evolution. Global expansion of human as a biological species in the context of the major evolutionary forces.

Main literature

1.     Hamilton M.B. Population genetics; edit. 2th. John Wiley and Sons Publisher, 2021.

2.     Allendorf F.W., Luikart G.H., Aitken. S.N. Conservation and the genetics of populations; edit. 2th. WileyBlackwell Ltd. Publication, 2012.

3.     Hedrick P.W. Genetics of populations; edit. 4th. Jones and Bartlett Publishers, Sudbury, Massachusetts, 2009.

4.     Conner J.K. Hartl D.L. Ekologinės genetikos pradmenys.Vilniaus universiteto leidykla, 2007.

5.     Frankham R. Ballou J.D. Briscoe D.A. A primer of conservation genetics. Cambridge University press, 2004.

6.     Beebe T.J. Rowe G. An introduction to molecular ecology. Oxford university press, 2004.

Assessment strategy

Assessment criteria

Exam or seminar

The doctoral student who has chosen the exam must answer three questions asked by the members of the commission from the main topics of the doctoral subject. Passing the exam requires positive evaluations of the answers to all three questions on a ten-point scale. From these estimates, an overall average score is calculated.

If choosing the seminar, the doctoral student makes a 20-30-minute presentation in which he/she discusses the doctoral topic from the position of ecological genetics, using at least ten scientific sources, considers the ecological genetics issues and concepts related to the topics. The knowledge demonstrated during the seminar, the ability to present it to the audience are assessed by the ten-point scale.

Vaidotas Morkūnas

Ph. D.

Ass. Prof.

Approved by the Council of Graduate School of Life Sciences Center No 600000-…-… on the …. of …… 2021

Chairman