What examples can illustrate the selective activity of genes in cells of various tissues?

The selective activity of genes is affected by displacements (morpho-genetic movements) of cells, their spatial location. They are provided by the ability of cells to actively move and adhere (selective formation of contacts with each other, in which glycocalyx plays an important role). Neighboring cells exert physical, chemical, and other influences on the cells that migrated and came into contact with them, selectively activating and inactivating the genes of their nuclei. Morphogenetic movement of cells is one of the mechanisms of selective activation of genes.
The differential activity of genes is influenced by hormones that are secreted by specialized cells and purposefully act on other cells and tissues. In mammals, more than 40 hormones are known. There are 3 groups of hormones: a) peptide and protein (insulin, growth hormone, prolactin, luteinizing, etc.); b) derivatives of amino acids (adrenaline, norepinephrine, thyroxine); c) steroid (androgens and estrogens). Under the control of hormones, all the basic processes of cellular metabolism (starting with the zygote), including transcription of the genome, regulation of gene activity, occur.

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