2014 METHODS OF RESEARCH INTO HUMAN GENETICS Výukový materiál GE 02 - 56 Tvůrce: Mgr. Šárka...

2014

METHODS OF RESEARCH INTO HUMAN GENETICS

Výukový materiál GE 02 - 56

Tvůrce: Mgr. Šárka Vopěnková

Tvůrce anglické verze: ThMgr. Ing. Jiří Foller

Projekt: S anglickým jazykem do dalších předmětů

Registrační číslo: CZ.1.07/1.1.36/03.0005

Tento projekt je spolufinancován ESF a SR ČR

human genetics differs from genetics of plants, fungi, animals and bacteria:

moral a ethic reasons human has in life a very small number of

descendants phenotype is in a very big measure influenced by the

external environment (social conditions) - polygenic features

generation period of a person is very long geneticist can observe maximally only 4 generations human genome is very complex

RESEARCH METHODS

specific observational methods:

1. research into family trees – genealogic method

2. research into twins – gemellological method

3. methods of population genetics

4. research into karyotypes

5. biochemical and molecular-genetic methods

RESEARCH METHODS

research into family trees – genealogic method : based on arrangement of family trees generation period of human = 20 – 25 let >

maximally observed 4 generations by monogenic features can be detected: feature conditioned by a dominant / recessive

allele feature is on autosome / gonosome

RESEARCH METHODS

result of research: determination of probability of

occurrence of the disease by the descendants

principal method by the diagnosis of hereditary diseases

used international symbols > e.g.. proband

RESEARCH METHODS

research into twins: a) twins originate from only one egg fertilized

by one sperm 100 % accordance of genome monozygotic twins MZ identical sex b) twins originate by fertilization of two eggs

by two sperms 50% accordance of genome dizygotic twins DZ identical or different sex

RESEARCH METHODS

monozygotic twins: MZ phenotype variations are consequence of the

non-hereditary component of variability by means of the phenotype accordance and

differences by MZ and DZ twins can be determined the mass of influence of hereditary and non-hereditary component of variability

disease with a high heritability > hereditary disease, can be predicted

disease with a high heritability > better curable

RESEARCH METHODS

research into karyotypes: cytogenetic research of chromosomes in the nucleus 23 pairs of chromosomes 220 pairs of autosomes + 1 pair of

gonosomes according to Denver nomenclature > in 7

groups A to G in agreement with their size and placing of centromeres

RESEARCH METHODS

biochemical and molecular-genetic many diseases caused by mutations defect alleles are mostly recessive ill people are also recessive heterozygotes > autosomal recessive heredity these diseases are caused by mutations of

structural genes = molecular diseases e.g.: phenylketonuria, galactosemia a

albinism

RESEARCH METHODS

handicapped child from its birth up to 15 years of age - special diet

organized a wide recapture of new born babies on the base of a simple biochemical examination

RESEARCH METHODS

DNA diagnostics: molecular-genetic method used in prenatal diagnostics e.g. Sickle-cell anaemia - disease: stricken only homozygotes ( SS) foe

defect allele S they have got erythrocytes of sickle

shape

GENETIC PREVENTION AND COUNSELLING

a big research project HGP deals with mapping of human genome started in 1990 by 2000 -2003 read the sequence of

human genome human has got 30 000 genes 98,5 % genes have a non-coding

sequence

RESEARCH METHODS

genetic counselling: an important part of preventive medicine medicine genetics department – hospitals: specification of diagnosis determination of risk of disabled children in

a high-risk family interruption essential principle of genetic counselling: guarantee of free (both) parents´ decision !!!

RESEARCH METHODS

eugenics: science struggling for improvement of biological

and mental quality of human population most effective reduction possibility of birth disabled

humans most effective reduction possibility of transmission

indisposed alleles into following generations hardly solvable contradiction: frequency of defect alleles in the populations

increases thanks to medicine (individuals with serious hereditary diseases are saved)

RESEARCH METHODS

Internationally given symbols, from which are created genealogical tables (family trees).

FILL IN THE SCHEMA

WORKSHEET

CHALUPOVÁ-KARLOVSKÁ, Vlastimila. Obecná biologie: středoškolská učebnice : evoluce, biologie buňky, genetika : s 558 řešenými testovými otázkami. 2., opr. vyd. Olomouc: Nakladatelství Olomouc, 2010, 206 s. ISBN 978-80-7182-282-0

SOURCES