What are the common cytogenetic techniques used for diagnosing genetic disorders?
Common cytogenetic techniques for diagnosing genetic disorders include karyotyping, fluorescence in situ hybridization (FISH), and array comparative genomic hybridization (aCGH). Karyotyping identifies large chromosomal abnormalities, FISH detects specific DNA sequences, and aCGH detects copy number variations across the genome.
How do cytogenetic techniques differ from molecular genetic techniques?
Cytogenetic techniques analyze the structure, number, and behavior of chromosomes using methods like karyotyping and FISH to detect chromosomal abnormalities. Molecular genetic techniques focus on the molecular aspect, studying DNA or RNA sequences for specific genes or mutations using methods like PCR and sequencing.
Are cytogenetic techniques used in cancer research and diagnosis?
Yes, cytogenetic techniques are widely used in cancer research and diagnosis. They help detect chromosomal abnormalities and genetic mutations associated with different types of cancer, guiding treatment options and prognosis. Techniques like karyotyping, fluorescence in situ hybridization (FISH), and comparative genomic hybridization (CGH) are commonly employed for this purpose.
How are samples prepared for cytogenetic analysis?
Samples for cytogenetic analysis are prepared by culturing cells, arresting them in metaphase using colcemid, hypotonic treatment to swell cells, and fixation with methanol-acetic acid. The fixed cells are dropped onto slides for spreading chromosomes, which are then stained or further processed for microscopic examination.
What are the limitations of cytogenetic techniques in genetic research?
Cytogenetic techniques have limitations such as low resolution in detecting small genetic changes, inability to identify single nucleotide polymorphisms, and difficulty analyzing complex chromosomal rearrangements. They often require dividing cells, which can limit the scope of samples. Additionally, these techniques may be less effective for detecting submicroscopic deletions or duplications.