By Seth Nagy
Farming is a great way to learn about nature, biology, engineering, and so many other parts of life. Recently, someone asked me about a cow that had twin calves. One calf was black with a white head, and the other was red with a white head. Both the bull and the cow had black bodies, and the cow had a white head. The big question was: How can two black animals have a red calf?
The answer comes from the work of a German monk named Gregor Mendel. In 1866, he published findings that became the foundation of modern genetics. He experimented with honeybees, mice, hawkweed, and especially pea plants. His pea research is what made him famous, though his work was largely overlooked until it was rediscovered after his death.
Mendel is credited with several key ideas. He developed the concept of dominant and recessive traits. He didn’t know about DNA or genes (that discovery came much later, in 1953, with James Watson and Francis Crick), but he figured out how traits are passed from parents to offspring. He showed how some traits can skip a generation and then reappear in very specific ratios.
He also worked out the ideas we now call genotype (the genetic makeup) and phenotype (the physical appearance), even though he used different words for them. We still use letters today to represent traits: capital letters for dominant traits and lowercase letters for recessive ones.
Using this system, we can map out the genetics of animals and see what combinations of genes the parents pass on to their calves. This is the key to understanding inheritance.
Source : ncsu.edu