SNPs can be detected by microarrays, which are wafer-like substrates to which millions of short stretches of DNA are attached. A microarray consists of many different squares, each one containing a different sequence of single-stranded DNA to which fluorescently labeled strands of DNAs from patients with different SNPs can hybridize. If one square will hybridize with an SNP having a C-G base pair at a particular site and an adjacent square will hybridize with an SNP having a T-A base pair at the same site, which of the following genotypes will hybridize with both squares and make them fluoresce?
A)the homozygous C-G/C-G genotype
B)the homozygous T-A/T-A genotype
C)the heterozygous C-G/T-A genotype
D)None of the answer options is correct; all of the genotypes hybridize with both squares.

Question

Quizplus · Accepted Answer

The heterozygous C-G/T-A genotype will have one allele with a C-G base pair at the site where the first square hybridizes and the other allele with a T-A base pair at the site where the adjacent square hybridizes. Therefore, this genotype will hybridize with both squares and make them fluoresce. The homozygous genotypes (C-G/C-G and T-A/T-A) will only hybridize with one of the squares, not both. None of the answer options hybridize with both squares, so D is not correct.

SNPs Can Be Detected by Microarrays, Which Are Wafer-Like Substrates