Figure Detail. As mentioned, sickle-cell anemia is the result of a change in a single nucleotide, and it represents just one class of mutations called point mutations. Changes in the DNA sequence can also occur at the level of the chromosome, in which large segments of chromosomes are altered.he result is the deletion of a DNA sequence in one chromosome, and the insertion of a DNA sequence in the other chromosome. Â© 2014 Nature Education Adapted from Pierce, Benjamin. Genetics: A Conceptual Approach, 2nd ed.
Also established in 1984, the Texas Division of Southwestern Bell Telephone, with headquarters at Dallas, became one of the largest nongovernmental employers in the state, serving 6.2 million customers in 549 Texas communities.
By LETTICE STUART. Published: November 22, 1992. SAN ANTONIO, TEX.â TWO months ago Southwestern Bell Corporation sent spirits flying in San Antonio, spread dejection in the St. Louis area and demonstrated again Mexico's importance to the economy of the Southwest.