Keyword Hot Links for chapter 3

The Mendel's paper is one of the few 19th century scientific papers that reads almost as clearly as if it had been written today. It is important reading for every aspiring geneticist. You can access a conveniently annotated text using the keyword Mendel. Although modern geneticists make a clear distinction between genotype and phenotype, Mendel made no clear distinction between these concepts. At this keyword site you will find a treasure-trove of information about Mendel, including his famous paper, essays, commentary, and a collection of images—all richly linked to additional Internet resources.

Huntington disease is a devastating degeneration of the brain that begins in middle life. It affects about 30,000 Americans, and each of their 150,000 siblings and children have a 50–50 chance of developing the disease due to its dominant mode of inheritance and complete penetrance. Named after George Huntington, a Long Island physician who first described the disease in 1872, the principal symptom is an involuntary, jerky motion of the head, trunk, and limbs called chorea, after the Greek word for "dance." At this keyword site you can learn about genetic testing programs, early symptoms, and the time course of the disease.

The red or purple colors of flowers, as well as of autumn leaves, result from members of a class of pigments called anthocyanins. The biochemical pathway for anthrocyanin synthesis in the snapdragon, Antirrhinum majus, can be found at this keyword site. The enzyme responsible for the first step in the pathway (chalcone synthase) limits the amount of pigment formed, which explains why red and white flowers in Antirrhinum show incomplete dominance.

Back to Keyword Hot Links for all chapters

Back to eLearning for all chapters