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#genetic testing

9 public questions tagged with this topic.

Which technique would best identify more than 1000 differentially expressed genes in one test?

A transcriptome microarray, also called expression array, contains probes for all annotated genes or entire transcriptome represented as tens of thousands of spots on a chip. Single hybridization of labeled cDNA from experimental and control samples allows parallel assessment of expression differences. Statistical analysis identifies hundreds to thousands of differentially expressed genes by fold change and p-value. RAPD assesses DNA polymorphism, genome sequencing determines DNA sequence rather than expression levels, and ChIP assesses protein-DNA interactions, making them unsuitable for simu

Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.

What feature allows rapid screening of Down syndrome in M-FISH?

M-FISH uses combinatorial fluorescence strategy where each chromosome is painted with a unique combination of fluorochromes, creating a distinct spectral signature decoded by software. Down syndrome results from trisomy 21. In M-FISH, chromosome 21 probes labeled with a specific fluorochrome combination appear thrice per metaphase spread instead of twice, readily identified by extra same-colored chromosome and automated image analysis. Color-coded fluorophores thus enable rapid whole-karyotype screening without chromosome-specific conventional G-banding expertise. Probe size, RNA tagging, and

Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.

In allele-specific hybridization, offspring I is positive only for the mutant probe. It is:

Allele-specific oligonucleotide hybridization uses labeled probes complementary to wild-type and mutant alleles to genotype individuals. Under stringent conditions, perfect match hybridizes strongly while mismatched probe shows negligible signal. An individual hybridizing exclusively to mutant probe carries mutant sequence on both homologous chromosomes, indicating homozygous mutant genotype expressing disease phenotype if recessive condition is pathogenic. Heterozygous carriers bind both probes, while unaffected homozygotes bind only wild-type probe. This differential hybridization enables ra

Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.