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.
When the tacos proved as popular as he had hoped, he started opening Taco Tia stands where tacos were the stars of the menu. In 1962, Bell sold the Taco Tia brand to his partners and opened the first Taco Bell in Downey, California. Franchising began two years later. Today, Taco Bell is a subsidiary of Yum! Brands Inc., which also franchises A&W Restaurants, KFC, Long John Silver's and Pizza Hut. There are Taco Bell locations throughout the United States and the world.