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Ecological and evolutionary consequences of polyploidization
Pavlíková, Zuzana ; Münzbergová, Zuzana (advisor) ; Rooks, Frederick (referee)
The frequency of polyploidy in natural populations is much more common than previously thought, suggesting that polyploidy must bring their holders either long or at least short term evolutionary advantage compared with their diploid ancestors, because otherwise they would not expand massively. The thesis deals with the consequences of polyploidy for genome, meiosis, mode of reproduction and the resulting viability of polyploid plants. It also describes and evaluates the possible reasons for the evolutionary success of polyploid plants. It also described the creation polyploids in diploid populations, the interactions between diploids and polyploids and the mechanisms of creation of reproductive isolation between cytotypes. Further, I paid attention to the interactions between polyploidy, herbivores and pollinators. In conclusion, I mention methods of synthesis neopolyploid plants, the possibility of their use and methods of detection of ploidy in plants.
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Ecological and evolutionary consequences of polyploidization
Pavlíková, Zuzana ; Münzbergová, Zuzana (advisor) ; Rooks, Frederick (referee)
The frequency of polyploidy in natural populations is much more common than previously thought, suggesting that polyploidy must bring their holders either long or at least short term evolutionary advantage compared with their diploid ancestors, because otherwise they would not expand massively. The thesis deals with the consequences of polyploidy for genome, meiosis, mode of reproduction and the resulting viability of polyploid plants. It also describes and evaluates the possible reasons for the evolutionary success of polyploid plants. It also described the creation polyploids in diploid populations, the interactions between diploids and polyploids and the mechanisms of creation of reproductive isolation between cytotypes. Further, I paid attention to the interactions between polyploidy, herbivores and pollinators. In conclusion, I mention methods of synthesis neopolyploid plants, the possibility of their use and methods of detection of ploidy in plants.
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The symptoms of Inbreeding depression in cattle
Kočková, Eva ; Hofmanová, Barbora (advisor) ; Vostrý, Luboš (referee)
In this work there was summarized knowledge about inbreeding and its influence on traits in cattle. Negative impacts of using this breeding are called an inbreeding depression and its noxiousness is different regarding the traits. Focus was given on economic impact which could inflict inbreeding depression.
This work also focuses on monitoring changes of inbreeding levels in individual population. In the last decades there was found an increase of inbreeding coefficient which is the result of intenzive selective breeding and using insemination. If this increase of inbreeding still persists, inbreeding depression will be a tremendous issue in the future.
All the authors of scientific works agreed on negative impact of inbreeding on production properties in cattle but the size of this impact and its consequences are considerably different due to individual attributes. The one of the biggest negative impacts which can have an influence on the economy of the breeding, appear in milk yeild (reduction of about 20 - 30 kg on 1 % of inbreeding coefficient), calving interval, age of first calving and days from calving to first insemination. Negligible negative result was found regarding the traits of meat production which does not have significant influence on economy of breeding. Inbreeding also has a minimal effect on the somatic cell score, but still increase the likelihood of developing mastitis in animals inbred compared to noninbred. Mastitis is considered as a serious diseases because of it could be a negative factor on economy of breeding.
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The negative effects of inbreeding in wild animals
Podhajecká, Iva ; Hofmanová, Barbora (advisor) ; Vostrý, Luboš (referee)
This bachelor thesis first explains the term of inbreeding itself, it also presents various definitions and patterns of inbreeding, that allow to determine the degree of inbreeding in an individual. Then it describes ways, in which inbreeding impacts population allele frequency and other effects influencing populations (e.g. Bottle-neck Effect, Founder Effect or Genetic Drift). Inbreeding is undesireable in nature, because it leads to inbreeding depression. That manifests itself by decreasing individuals fitness, which then has a substantial impact on populations dynamics. Main part of the thesis is then focused on wild populations of birds and mammals. The degree of inbreeding is most commonly assessed by pedigree analysis. That is a highly demanding method, as it requires a longterm population observation in the field and, in many cases, also tissue collection for genetic analysis. The last step is represented by thorough statistical analysis, allowing to determine kinship in population as precisely as possible. Based on pedigree, we can calculate coefficient of inbreeding 'F', which then allows us to determine the extent of inbreeding depression. The last part of the thesis describes effects of inbreeding on offspring fitness, reproductive success and immunity in avian and mammal populations. As each of the populations has different specifics, the base characteristics of a particular population are described first and then the impacts of inbreeding on individual fitness indicators are presented. As opposed to populations living in captivity, wild populations are adversely affected by other factors, mainly environmental, that can deepen inbreeding depression. Studies dealing with these issues are therefore extremely important, as their findings can be applied into improving of management and conservation of endangered species.
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