Mosaic forms
At mosaicism (mos) designate karyotype each an abnormal and normal clone of cells then write down in brackets [] number of the analysed cells, karyotypes different clones designate a virgule/. The normal clone is always designated by the last
The mosaic syndrome of Down (mos) 47, XX, +21 [60]/46, XX [40]: at the girl with the mosaic form s. Down from 100 cells 40 cells(cages) with normal karyotype and 60 cells with simple trisomy on 21 chromosome are revealed.
Turner's 45 mosaic syndrome, ХО, [80] / 46, XX [20] or 45, ХО [30] / 47, XXX [70].
Method of genetics of somatic cells
This method represents cultivation, cloning, hybridization and selection of somatic cells. CLONING – reception of descendants (the big number of cells) from one cell due to division. Clonable cells use for reception of the big number of cells for the chromosomal analysis, for studying features of metabolism, for the quantitative account of mutations, for the proof of heterogeneity of cellular populations.
Selection in genetics of somatic cells apply to selection of mutants on resistency, auxotrophency. Selection of mutants on resistency is based on their survival at the presence of some lethal factor. Selection auxotroph cells is based on their property to use for the growth strictly certain substances which are not synthesized by a cell.
By hybridization localization of genes in chromosomes is established. Hybridization is based on merging of together cultivated cells of two different types. Hybrid cells or heterokaryons contain nucleus with chromosomal complements of two different kinds, for example, the person and mice, the person and rat, the person and chinese hamster. Genotypes of such cells are in a condition of disbalance and so at cellular division heterokaryons usually lose a part of chromosomes. In different hybrid cells chromosomes of one kind are lost. In hybrid cells « the person - the mouse » chromosomes of the person gradually get lost. Gradual loss of chromosomes of the person can lead finally to preservation of a unique chromosome. So preservation of 9 chromosomes of the person in a hybrid cell « the person - the mouse » has allowed to establish, that cells of this clone have started to develop interferon in reply to introduction of a virus. Therefore have established, that the gene responsible for synthesis of interferon is located in 9 chromosome.
Methods of modeling.
Two methods are developed: biological and mathematical modelling.
Biological modelling is use of the animals having inheritable anomalies, corresponding to anomalies of the person. It is used in genetics for:
1.Studying pathogens of hereditary diseases.
2.Development of methods of their treatment.
Mathematical modelling is based on use of computer technologies. With the help of this method are studied:
1.Distribution of mutations to populations under different conditions of action of
selection.
2.Influence of experimental evolutionary factors in different combinations on a genofund
of populations at distribution of a hereditary pathology.
3.Effect of the linked inheritance at analysis of plenty of the linked genes
4.In medico-genetic consultation for the forecast of posterity.