Document-Based Questions - Debra J. Housel, M.S. Ed. 2008

Genes
Amazing Discoveries

One of the most important discoveries of the 20th century really occurred in the 19th century. It took many years for scientists to acknowledge the information. Here’s how it happened. In 1822, Gregor Mendel was born on a farm in Austria. His father encouraged his interest in plants. He saw that his son was smart. He wanted him to have an education. So he sent Mendel to high school. At that time few people went to high school. Those that did lived there and had to pay. Since his father could not pay the full tuition, Mendel received no food. The other students fed him their scraps. He always felt hungry.

When Mendel grew up, he became a monk. He tended the gardens where he and the other monks lived. For eight years he did experiments with pea plants. He had a theory. He thought that parent plants passed traits to their offspring.

He wanted to prove this. Over time he discovered that plants have genes. Genes carry codes for features from one generation to the next. Around 1860, Mendel found recessive and dominant genes. Dominant genes showed up often in offspring. Recessive genes did not show up often and only if both parents carried the gene.

How did he figure all this out? He bred a tall pea plant with a short pea plant. In the first generation each of the four pea plants was tall. This meant that tall was the dominant gene. But all four tall pea plants carried the recessive short gene. In the next generation of four pea plants one was short. The recessive short genes it got from both of the parent plants made it short.

Excited, Mendel published an article in 1866. No one paid any attention to it! He died 16 years before his great discovery was recognized in 1900. Today he is called the Father of Genetics.

We now know that both plants and animals have genes. They play a role in how we look, how we act, and whether or not we are apt to get certain diseases. Each human cell has between 20,000 and 30,000 genes.

Gene mapping has let people match certain traits with specific genes. This let scientists find ways to change genes in plant and animal cells. They have created crops that resist fungus. Fruit is bigger and less apt to get worms. They’ve made bigger chickens that have more white meat. A modern dairy cow gives ten times the milk that one did in 1900 due to selective breeding and gene alteration.

Genes

Genes

1. Gregor Mendel was the

a. first botanist (person who studies plants).

b. Father of Genetics.

c. only monk who ever grew plants.

d. smartest student in his high school.

2. Mendel discovered that a recessive gene shows up

a. in one plant and then never again.

b. in every generation of plants.

c. frequently in plants.

d. only if both parent plants carry it.

3. Mendel died in

a. 1822.

b. 1866.

c. 1884.

d. 1900.

4. Scientists are able to alter (change) genes in both plants and animals. True or False? Explain.

5. Give two reasons why Noah Grinder is against gene-altered foods.

6. Should the government ban (stop) gene-altered food? Why or why not?