Lecture Notes – Content Outline and Key Terms
Dogs are one of man’s longest genetic experiments.
Over thousands of years, humans have chosen and mated dogs with specific traits.
The result has been an incredibly diverse array of dogs with distinct
body types and
II. Mendel’s Laws
The science of genetics has ancient roots
Pangenesis, proposed around 400 B.C. by Hippocrates, was an early explanation for
inheritance that suggested that
particles called pangenes came from all parts of the organism to be incorporated
into eggs or sperm, and
characteristics acquired during the parents’ lifetime could be transferred to the
Aristotle rejected pangenesis and argued that instead of particles, the
produce the traits was inherited.
The idea that hereditary materials mix in forming offspring, called the blending
suggested in the 19
century by scientists studying plants but
later rejected because it did not explain how traits that disappear in one generation
can reappear in later generations.
Experimental genetics began in an abbey garden
is the transmission of traits from one generation to the next.
is the scientific study of heredity.
began the field of genetics in the 1860s,
deduced the principles of genetics by breeding garden peas, and
relied upon a background of mathematics, physics, and chemistry.
In 1866, Mendel
correctly argued that parents pass on to their offspring discrete “heritable factors”
stressed that the heritable factors (today called genes), retain their individuality
generation after generation.
Heritable features that vary among individuals, such as flower color, are called a
Each variant for a character, such as purple or white flowers, is a
varieties result when self-fertilization produces offspring all identical
to the parent.
The offspring of two different varieties are
The cross-fertilization is a hybridization, or genetic