Chromosomes composed by thousands of genes, the chemical blueprints of all living things. Gene : 1. determiner for physical traits (eye color, blood type, bone structure) 2. impact behavioral traits (intelligence, temperament, and sociability) Made of DNA molecules, looking like a long double strand arranged in a spiraling staircase fashion. DNA composed of the same chemical bases, but the exact arrangement of chemicals varied, causing diff DNA to have diff effects. Dominance and Recessiveness
Ali might have received a gene for brown eyes from one parent and a gene for blue eyes from the other. It’s the principles of dominance and recessiveness would allow us to predict that the actual color of Ali’s eyes would be brown because genes for brown eyes are dominant over blue eye genes.
Dominant gene is one that is always expressed in the phenotype (the gene that prevails when paired with a subordinate or recessive gene) Recessive gene is one that may be expressed only in the absence of a dominant gene, or when it is paired with a similar recessive gene. Multifactorial inheritance; more complicated form of genetic transmission, in which several gene pairs interact.