After G-banding analysis, which procedure would be most helpful in determining if a deletion has occurred in chromosome 10?

Fluorescence In Situ Hybridization (FISH) is the most effective method for detecting specific chromosomal abnormalities, such as deletions, following G-banding analysis. This technique involves the use of fluorescently labeled DNA probes that bind to specific regions of chromosomes. When a deletion occurs on a chromosome, the corresponding probe may not hybridize due to the absence of that chromosomal segment. Thus, FISH can visually confirm the presence or absence of genetic material, allowing for the clear identification of deletions that may not be evident through G-banding alone.

In contrast, other methods like NOR banding, C-banding, and Q-banding have different applications. NOR banding is specific for identifying nucleolar organizing regions but does not provide the fine resolution necessary for detecting deletions. C-banding is useful for visualizing centromeres and heterochromatin but is not ideal for pinpointing specific deletions across the chromosome. Similarly, Q-banding highlights the distribution of fluorescent bands on chromosomes but doesn’t offer the specificity needed to identify the absence of sections of DNA, such as in the case of deletions. Therefore, FISH stands out as the preferred choice for confirming deletions identified through initial G-banding analysis.