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New possibilities to distinguish monozygotic twins
Letková, Kristína ; Kulichová, Iva (advisor) ; Priehodová, Edita (referee)
The necessity of distinguishing monozygotic twins from a genetic point of view is important not only for determining paternity, when it is decided which of two identical twins is the father, but also, for example, for criminal cases, where it is necessary to identify the perpetrator who is one of the monozygotic twins. In addition to analyzing and evaluating molecular biological methods, the work also deals with monozygotic twins themselves, their emergence and the causes of their emergence. The topic affects both forensic genetics and medical fields.
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Human FADS genes and their adaptive evolution
Motysová, Natalia ; Priehodová, Edita (advisor) ; Kulichová, Iva (referee)
Long chain polyunsaturated fatty acids (LC-PUFA) are one of the key elements that help maintain the optimal health of our organism. Our body is unable to synthesize them de novo, thus we need to synthesize them using various enzymes including desaturases from the diet's precursors. The FADS1 and FADS2 genes encode Δ5D (FADS1) and Δ6D (FADS2) desaturases, which catalyse the desaturation steps of LC-PUFA biosynthesis. Within the FADS gene region, different genetic variants affecting desaturase activity have been identified, one example being single nucleotide mutations forming two haplotypes A (ancestral) and D (derived), a classification later redefined to haplogroup A and D. The activity of Δ5D and Δ6D fatty acid desaturases are influenced by the haplogroup. Individuals with haplogroup D show a higher level of FADS1 gene expression and haplogroup D is also associated with a more efficient conversion of 18-carbon PUFAs to LC-PUFAs. However, this feature varies across populations. Different types of environments require diverse adaptations, and it is adaptation to diet that is very evident in the FADS gene cluster. Higher FADS1 expression and more efficient conversion of 18-carbon PUFAs to LC-PUFAs will be favored in environments with reduced availability of these acids (Africa, India). On the...
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Age estimation from human biological material based on DNA methylation
Matoušková, Laura ; Kulichová, Iva (advisor) ; Priehodová, Edita (referee)
DNA methylation is one of the epigenetics modifications which performs many functions in human body by silencing genes and maintaining genomic stability. Changes in DNA methylation accumulate during life and current studies indicate that the level of methylation in certain loci (CpG dinucletotides) correlates with chronological age. However, the methylation pattern changes not only with increasing age but it can also be affected by our lifestyle choices and biogeographical origin. Therefore, the key for succesful age estimation is finding such CpG loci that are independent (or as little dependent as possible) on other variables. This bachelor thesis describes the issue of age estimation based on DNA analysis of specific methylated DNA loci with focus on its application in forensic practice.
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Population of African Sahel according to phylogeography of Eurasian haplogroups
Kulichová, Iva ; Černý, Viktor (advisor) ; Macholán, Miloš (referee)
The thesis is focused on two mtDNA haplogroups of Eurasian origin that occur mostly among the Fulani, herders of the African Sahel. On the initial analysis 544 DNA samples from unrelated Fulani individuals were used. These samples were classified to haplogroups according to hypervariable segment I (HVS-I) of mtDNA and subsequently, specific Eurasian haplotypes were chosen for the whole mtDNA genome sequencing. Obtained mito-genomes were assigned to phylogenetic trees and dated. It turned out that they belonged to haplogroups U5b1b1b and H1ca1a with the probable origin in the Iberian Peninsula, presumably in Franco-Cantabrian refugium where their ancestors originated in the period between the Late Glacial and the first half of the Holocene. Afterwards they migrated through the Strait of Gibraltar to North Africa and the Sahara, where the proto-Fulani pastoral population was being formed. It may also be assumed that a part of this population came to Africa from the Near East, along with cattle. In the second half of the Holocene, this pastoral population migrated from the drying Sahara to the Sahel. Probably due to small number of female migrants the females from the local populations were integrated, which explains the major representation of West African mtDNA haplogroups in contemporary Fulani....
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Mutation rates and dispersal of human populations
Kulichová, Iva ; Černý, Viktor (advisor) ; Šolc, Roman (referee)
This bachelor thesis deals with estimation of mutation rate of DNA and its use for dating of the first settlement of Sahul. The first part describes direct approach for the estimation of the mutation rate, based on the analysis of pedigrees and indirect approach based on phylogenetic analysis. The weaknesses of these methods are presented as well, as they distort the resulting values of the mutation rate and therefore it is necessary not to ingore them. Some alternatives of calibration methods for the direct and the indirect estimation of the mutation rate are introduced, for example based on archaeological samples. The subsequent section discusses the characteristic mutation rate of mitochondrial and nuclear DNA estimated utilising the direct and the indirect approach. The difference between pedigree and phylogenetic rates appears especially in the mitochondrial DNA, because of selection.The second part outlines the evolutionary path leading to anatomically modern human in Africa and his expansion into Eurasia based on the fossil record dated 45,000 years ago. Particular attention is paid to the settlement of Sahul in archaeological and molecular point of view. Based on the combination of these sources of information, it is possible to conclude that the settlement of Sahul passed from Africa along...
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