Tsütogeneetika

Tsütogeneetika, also known as cytogenetics, is the branch of genetics that studies the structure, number, and behavior of chromosomes in cells, and how chromosomal variations relate to development, health, and disease. Traditional cytogenetics relies on visualizing chromosomes in metaphase spreads obtained from cultured cells, followed by staining to reveal characteristic banding patterns that identify each chromosome. This allows detection of numerical abnormalities (such as trisomies and monosomies) and structural changes (deletions, duplications, translocations, inversions).

Beyond conventional karyotyping, modern cytogenetics uses molecular techniques such as fluorescence in situ hybridization (FISH) to detect specific sequences; spectral karyotyping (SKY) for multicolor chromosome painting; chromosomal microarray analysis or comparative genomic hybridization (aCGH/array-CGH) to map copy-number variations at high resolution; and sequencing-based approaches that integrate cytogenetic information with next-generation sequencing.

Applications include diagnostic testing for congenital anomalies and developmental disorders, cancer cytogenetics (characteristic chromosomal alterations in leukemias, lymphomas, and solid tumors), and prenatal screening. In prenatal diagnostics, samples from amniocentesis or chorionic villus sampling are analyzed to detect chromosomal abnormalities, while non-invasive prenatal testing uses cell-free fetal DNA to assess risk for common aneuploidies before invasive testing.

Limitations include resolution differences: karyotyping detects large rearrangements, while some balanced rearrangements may be missed by microarrays; not all alterations are detectable by a single method. The field continues to evolve with higher-resolution genomic technologies, digital imaging, and integrated analyses that combine cytogenetic structure with molecular data to improve diagnosis and understanding of genomic disorders.