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.
CenturyLink History. CenturyLink was founded in 1968 as Central Telephone and Electronics Corporation. In 1971, the name was changed to Century Telephone Enterprises and then to CenturyTel in 1999. Oak Ridge Telephone Company originally served 3 states with around 10,000 access lines.