In a FISH analysis, a cloned probe of a single-copy gene hybridizes to cells in mitotic metaphase. How many fluorescent spots will be seen in one cell?

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∻Answer∻ ⚹ 4 fluorescent spots ⚹ ∻Solution∻ ‖ a ⋮ In a FISH (Fluorescence In Situ Hybridization) analysis, a cloned probe of a single-copy gene hybridizes to specific DNA sequences in the chromosomes. ‖ ‖ b ⋮ During mitotic metaphase, chromosomes are duplicated and aligned at the metaphase plate. Each chromosome consists of two sister chromatids. ‖ ‖ c ⋮ Since the gene is single-copy, each chromatid will have one copy of the gene. Therefore, each chromosome will have two copies of the gene, one on each chromatid. ‖ ‖ d ⋮ Humans have 23 pairs of chromosomes, but for a single-copy gene, we focus on one pair. Each pair will have 2 chromosomes, and each chromosome will have 2 chromatids. ‖ ‖ e ⋮ Thus, in one cell during mitotic metaphase, there will be 4 fluorescent spots (2 chromatids per chromosome × 2 chromosomes). ‖ ∻Key Concept∻ ⚹ Single-copy gene hybridization during mitotic metaphase results in 4 fluorescent spots per cell. ⚹ ∻Explanation∻ ⚹ During mitotic metaphase, chromosomes are duplicated and consist of two sister chromatids. Each chromatid contains one copy of the single-copy gene, resulting in 4 fluorescent spots per cell. ⚹◊What is the role of FISH analysis in studying gene copy number variations in cells?⍭ Generate me a similar question◊

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