3Tashkent Medical Academy Integration of Science, Education and Practice in Modern Psychology and Pedagogy: Problems and Solutions
Volume 4 | TMA Conference | 2023 Zamonaviy psixologiya, pedagogikada fan, ta'lim va amaliyot integratsiyasi: muammo va yechimlar
PRACTICAL LESSON ON METHODS OF STUDYING HUMAN GENETICS
Z. Y. Tillayeva
Head teacher of biology, candidate of biological sciences,
A. Zaydulin
2Student Academic Lyceum of the Tashkent State Institute of Dentistry,
Tashkent city
ANNOTATSIYA
Maqolada antropogenetika bo'yicha amaliy mashg'ulot o'tish usullari yoritilgan. O'quvchilar kariotip tuzib, irsiy kasalliklarni aniqlaydilar va shu orqali nazariy bilimlarini amaliyotga qo'llaydilar. Geneologik usul yordamida o'z shajaralarini tuzib, ularni tahlil qiladilar. Populyatsion-statistik usul yordamida irsiy kasalliklarning tarqalganlik darajasi aniqlanadi.
Kalit so'zlar: antropogenetika, sitogenetika, xromosoma, proband.
АННОТАЦИЯ
В данном статье дается рекомендации по проведению практических работ. Ученики в практике закрепляют свои теоретические знания и узнают о создании кариотипа, о наследственных заболеваниях. С помощью генеалогического метода изучают составление родословной. Популяционно-статистический метод позволяет изучать распространенность наследственных болезней.
Ключевые слова: антропогенетика, цитогенетика, хромосома, пробанд
ABSTRACT
This article provides recommendations on practical biology lessons. Student during such lessons consolidate their theoretical knowledge. By completing tasks presented in the article, students will learn about the creation of karyotype and hereditary diseases. With the genealogical method, the preparation of a pedigree is studied. The population-based statistical method allows us to study the prevalence of inheritable diseases.
Keywords: anthropogenetics, cytogenetics, karyotype, chromosome, proband.
In recent years, interest in genetics has particularly risen, as its practical value for humanity is undeniable.
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Tashkent Medical Academy Integration of Science, Education and Practice in Modern Psychology and Pedagogy: Problems and Solutions
Volume 4 | TMA Conference | 2023 Zamonaviy psixologiya, pedagogikada fan, ta'lim va amaliyot integratsiyasi:
vechimlar
muammo va
ye
Human genetics or anthropogenetics studies problems such as the detection, prevention and treatment of hereditary diseases. Experts use a number of methods to study human genetics. One of them is the cytogenetic method, through which visible changes in the human chromosome set are studied. To study chromosomes, blood is taken, white blood cells are separated by centrifugation and grown in an artificial environment at 37° C. To stop cell division at the metaphase stage, colchicine is added. Chromosomes are photographed using an electron microscope.
Firstly, the cytogenetic method is studied and students will make their own simulation of the human karyotype. Students theoretically learn the sequence of chromosome allocation. During practical work, the chromosomes are cut using pre-prepared image. Then homologous chromosomes are placed next to each other in pairs and pasted to the notebooks in order, beginning with the largest ones and ending with the smallest. All pairs are numbered. As it is known, the total amount of chromosome pairs in the karyotype of the human without any diseases should be 23. There are 45 chromosomes, with one last sex chromosome missing, and 47 chromosomes in the pictures 1a and 1b respectively.
Sex chromosomes, which should be at the end, are depicted by dotted lines in the picture. Students have to make a diagnosis and give short description of the genetic disorder after finishing the karyotype. In picture 1a, the diagnosis is Turner syndrome (TS), also known as 45, X; in the picture 1b - Down syndrome, also known as trisomy 21.
Secondly, the genealogical method is used by the students. This method involves the analysis of pedigree charts, hence it helps to determine the type of inheritance of genetic diseases. Four different inheritance types can be identified by pedigree chart analysis: autosomal dominant, autosomal recessive, X-linked, or Y-linked. After gaining theoretical knowledge, students make a pedigree chart of their own family and do following tasks.
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Tashkent Medical Academy Integration of Science, Education and Practice in Modern Psychology and Pedagogy: Problems and Solutions
Volume 4 | TMA Conference | 2023 Zamonaviy psixologiya, pedagogikada fan, ta'lim va amaliyot integratsiyasi:
vechimlar
muammo va
ye
Task 1. Analyze the pedigree chart given below, identify the type of inheritance and calculate the percentage of offspring with a genetic trait in question.
Answer: Considering that the trait occurs in each generation and does not depend on the gender of a proband, the inheritance type is autosomal dominant; 72 percent of offspring are affected.
Task 2. Analyze the pedigree chart given below, identify diseased people among marked with numbers 1-7 and indicate their gender. Calculate the percentage of
unaffected members of the family.
Answer: 1, 3, 7 - ill females; 2- an ill male; the percentage is 62.5%.
Task 3. 1. Analyze the pedigree chart given below, identify the type of inheritance and the genotype of the marked proband.
Tashkent Medical Academy Volume 4 | TMA Conference | 2023
Integration of Science, Education and Practice Zamonaviy psixologiya, pedagogikada fan,
in Modern Psychology and Pedagogy: ta'lim va amaliyot integratsiyasi:
Answer: Considering that the trait occurs in each generation and does not depend on the gender of a proband, the inheritance type is autosomal dominant. The proband is heterozygous.
Task 4. Proband is suffering from epilepsy. Both of his brothers and his mother are diseased. Proband's father does not have epilepsy. His maternal grandmother is affected by the disease, unlike his maternal grandfather. The grandmother's father, sister and father's brother were ill too. They got the disease from their father. The grandfather's great grandfather, his brother, daughter and 2 sons were diseased. The proband's wife and her relatives are not affected by the epilepsy. Calculate the percentage of affected by the disease people in the family.
The third method used in human genetics is the population statistical method. This method is used to calculate the probability of a genetic trait occurring in the population. This method is based on mathematical calculations and integrate biology with mathematics. The Hardy-Weinberg principle is used in population genetics. Mathematically, The Hardy-Weinberg principle is expressed:
p2 + 2pq + q2 = 1; p + q = 1; q = 1 - p p - frequency of the dominant allele, q - frequency of the recessive allele, p2 - frequency of the dominant homozygotes, q2 - frequency of the recessive homozygotes, 2pq - frequency of the heterozygotes.
Task 5. In a stable population, the frequency of frequency of the recessive allele is equal to 0.2; the frequency of the dominant allele is equal to 0.8. Calculate the frequency of heterozygotes in the population. Answer: 2pq = 2 * 0.2 * 0.8 = 0.32.
Task 6. Albinism is a hereditary disease characterized in humans by the partial or complete absence of pigment in the skin, hair and eyes. Calculate the percentage of people with the albinism gene but not affected by the disease, if the occurrence of affected people in the population is 1 in 10000.
Answer: q2 = q = V0.0001 = 0.01;
M 10000' M '
p = 1 - 0.01 = 0.99; 2pq = 2 * 0.01 * 0.99 = 0.0198 « 0.02 = 2%.
Practical lessons have a crucial role in studying of biology and help to strengthen practical knowledge, while teaching the students to be responsible and socially active.
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Tashkent Medical Academy Integration of Science, Education and Practice in Modern Psychology and Pedagogy: Problems and Solutions
Volume 4 | TMA Conference | 2023 Zamonaviy psixologiya, pedagogikada fan, ta'lim va amaliyot integratsiyasi: muammo va yechimlar
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2. П.Р. Алимходжаева и другие. Сборник задач по общей и медицинской генетике // Т.: «Кохи-Нур» - 2009 - С. 71-73
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