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Associations between red colour of hair and other morphological, physiological, and behavioral traits
Musil, Martin ; Flegr, Jaroslav (advisor) ; Fiala, Vojtěch (referee)
Hair and skin colour are one of the most visible external features that can be encountered in humans. Red hair colour is the least common colour. It is associated with fair skin, which is prone to ultraviolet radiation. This is captured by eumelanin, which is less common in redheads because they have more pheomelanin pigment. Because of this, red-haired people are in a higher risk of developing malignant melanoma. This risk is further increased by more freckles and nevi on the skin. The major gene behind red hair is MC1R. This gene forms a receptor that binds hormones that regulate pigment production. Red-haired people have a gene allele that is demonstrated by partial or complete loss of MC1R receptor function. According to some studies, red hair also affects how red-haired people feel pain and whether they need more anaesthetics to induce general anaesthesia. The practical part of this work consists of a survey which topics are covered in published studies that mention red hairs in their title or abstract. The survey was conducted on three search engine Web of science, Google scholar and PubMed. All databases contained the most articles that linked red hairs as a risk for malignant melanoma. Key words: redhair, phenotype, human, eumelanin, pheomelanin, pigmentation, melanoma
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Changes in pigmentation of animals during domestication
Ariskina, Sofya ; Hofmanová, Barbora (advisor) ; Kracíková, Olga (referee)
In this work there are described, based on different experiments, and on the basis of them written articles about changes of different types of animals in the course of domestikation. It is supposed that this process began 15 thousand years ago. Here a described main scenarios which show the reasons and ways of the beginning of domestication, and some main places where this process began.
But it is much more important that in the course of the domestication there was a big number of morphological, anatomic and physiological changes in which consequence wild animals gradually turned into domestic ones. These changes, whether it be considerable change of the corporal sizes, reduction of a brain, changes in nervous system, emergence of trailing ears or big quantity of various coat colors, testifies that animals lost the need to survive independently and began to depend partially or completely on people.
But a main goal of this work is to describe and explain the development of new, not existing in wild animals coat colors which are connected to the domestication process and, later, to the selection process, made by people. The general sign of all domesticated animals chosen and selected incidentally or intentionally on any signs is emergence of spottiness and heterogeneity of coat coloring, gradually turning into other colourings that are absolutely not typical for wild animals because in the wild nature would draw attention of predators or mark.
Also here is described the genetic component of process of emergence of new coat colors caused by a different ratio of an eumelanin and a feomelanin, and also various gene mutations (for ex. MC1R, ASIP ets.).
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Genetika zbarvení činčil
Poslušná, Michala
There are same principles for color coat genesis for all mammals, both on a molecular level and when the final phenotype is created. Even in the early embryonic stage the cells for pigment deposition are distributed to the periphery parts of the body, skin cells and hairfollicles. The most important substance for color coat genesis is melanin pigment, whose synthesis is affected by melanocortin and two basic pigments eumelanin a pheomelanin are made by enzymatic cycles. The final phenotype is influenced by 5 or 6 basic genes, their mutations and interaction between them. Model system for showing the creation of color coat is mice. Chinchilla's, whom the work is dedicated to, genes and alelles haven't been described in exact way yet, but it is supposed, that basic principles are the same as in mice and the knowledge of color coat genetics in rodents are based on this claim. Breeders use allele indication made by themselves and genotype is determined by the animal's phenotype. The phenotype of offspring is determined by genotype of both parents.
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