Rachel N. Grob
Genetic theorists assert that we can explain human characteristics, health, and/or behavior, to a significant degree, by the deoxyribonucleic acid (DNA) sequence present in the genes of a person or of a group of people presumed to have meaningful genetic similarity. Since the beginning of the 20th century, when they rediscovered the earlier published work of Czechoslovakian monk Gregor Mendel, Western scientists have agreed that recessive and dominant factors of heredity govern numerous human traits (such as eye color). Two contributing alleles determine these traits, one from each parent, with dominant factors always physically expressed, as they have the power to mask recessive ones. Scientists call these factors genes —although this term was (and some argue still is) quite imprecise—and they conceptualize genes as clustered together on chromosomes. By the 1950s, biologists had demonstrated that the DNA within genes influences heredity, and in 1953, scientists lames Watson and Francis Today, ...