What is the third DNA/chromosomal level method for genetic testing, alongside in situ hybridization and karyotyping?

• A. RNA sequencing
• B. Methylation analysis
• C. DNA sequencing
• D. Chromosomal translocation

Answer: (C)

The third DNA/chromosomal level method for genetic testing, alongside in situ hybridization and karyotyping, is DNA sequencing. This technique allows for the determination of the exact sequence of nucleotides in a DNA molecule. It is a critical method for identifying genetic variants that may contribute to diseases or other phenotypic traits. DNA sequencing provides a more detailed look at the genetic information compared to karyotyping, which examines the number and structure of chromosomes, and in situ hybridization, which helps identify the location of specific DNA sequences within the chromosomes.

DNA sequencing can uncover mutations at the base pair level, offering insights that are essential for personalized medicine, gene therapy, and understanding genetic disorders. It is also a foundational tool in genomics for research purposes, enabling scientists to study gene function and expression patterns. This makes DNA sequencing a vital addition to the genetic testing arsenal, complementary to the broader and more structural evaluations provided by the other two methods.