lecture 3 - cytogenetics Flashcards
What is cytogenetics
The study of the structure and function of DNA within the cell nucleus, particularly during cell division when it forms chromosomes.
Why is cytogenetics important?
It helps analyze chromosome number and morphology to diagnose genetic disorders.
What are the key techniques in cytogenetics?
Karyotyping, chromosome banding, and molecular techniques like FISH.
Give examples of pathologies with altered cytogenetic profiles.
Down syndrome (trisomy 21), Klinefelter syndrome (XXY), and Williams syndrome (chromosome 7 deletion).
What are the three types of cell division?
Mitosis, meiosis, and fertilization.
Why is proper chromosome number crucial in cell division?
Errors can lead to genetic disorders such as trisomy or monosomy.
How do scientists read chromosomes?
By analyzing size, banding pattern, and centromere position.
What is the role of centromeres?
They serve as attachment points for microtubules during cell division.
What is aneuploidy?
A loss or gain of entire chromosomes
What is trisomy?
A condition where there are three copies of a chromosome instead of two.
What is polyploidy?
A numerical change in the whole set of chromosomes.
What causes structural chromosomal abnormalities?
Breakage and repair of chromosomes.
Breakage and repair of chromosomes.
Fusion of the long arms of two acrocentric chromosomes, resulting in genetic material loss from the short arms.
What is mosaicism?
The presence of different genetic cell lines in an individual due to early mitotic errors.
Give an example of mosaicism.
Trisomy 21 mosaicism (some cells have 47 chromosomes, others have 46).
What is karyotyping?
A technique to count chromosomes and detect structural abnormalities.
What information does a karyotype provide?
The number and structure of chromosomes, which can indicate genetic disorders.
What does chromosome banding help identify?
Chromosome structure, deletions, translocations, and genetic changes.
What is Q-banding?
A technique using Quinacrine fluorescence to stain AT-rich DNA regions.
What is G-banding?
Giemsa stain highlights AT-rich regions, similar to Q-banding.
What is R-banding?
Reverse banding technique that stains GC-rich regions.
What is FISH used for?
To detect chromosome number and gene copy number by hybridizing fluorescent DNA probes.
What is M-FISH?
A multicolor FISH technique for fast automated karyotyping and translocation identification.
Which diseases are linked to chromosome 1?
Porphyria, prostate cancer, glaucoma.
Which diseases are linked to chromosome 7?
Cystic fibrosis, Type 2 diabetes, Burkitt’s lymphoma.
Which diseases are linked to chromosome X?
Hemophilia, color blindness, Fragile X syndrome.
What is unique about the Y chromosome?
It is much smaller than the X chromosome and carries genes like the SRY (testis-determining factor).
What is Klinefelter syndrome’s karyotype?
47,XXY.
What is the cause of Williams syndrome?
A deletion on chromosome 7 affecting connective tissue genes.
What is the Philadelphia chromosome?
A translocation between chromosomes 9 and 22, linked to chronic myeloid leukemia.
