THE HISTORY OF GENETICS

Genetics is the study of heredity and variation in living organisms. This section gives a brief history of the development of modern genetics, focusing on the work of Charles Darwin, the father of evolution, and Gregor Mendel, the father of genetics.

3.1.1 Charles Darwin

Charles Darwin was born in England in 1809, the son of the wealthy doctor Robert Darwin. Charles's privileged position in life allowed him to wander from one interest

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to another as a young man, apparently destined to waste his life in lazy meanderings.

His father was a hard-working man, but as often happens, hard work by the father resulted in laziness in the son. "You care for nothing but shooting, dogs, and rat-catching; and you will be a disgrace to yourself and all your family," Robert told his son [Darwin et al., 2002, page 10]. Robert tried to involve his son in his medical practice, but Charles was not interested, and besides, he hated the sight of blood.

So Robert sent his son to Cambridge University to study for the ministry.

Charles wasn't really interested in his studies at Cambridge; the only thing he was interested in was the outdoors. He spent all of his time exploring and studying nature, reading the books of great naturalists, and collecting beetles. His life began to take on some focus as he became more proficient as a naturalist. Charles began meeting professors and other students who shared his interest in nature. He began making plans to leave his ministerial studies and pursue his true passion in life. He was finally becoming ambitious.

In 1831, at the age of 22, Charles applied for a position on the Beagle, a ship that was commissioned to survey the southern tip of South America for the English government. Charles was accepted for the position under the condition that he pay his own way.

What would you do if you were the father of Charles Darwin? You've sent your son to school and have paid for three years of ministerial training, and now he comes to you asking for funds to pay for a five-year sea voyage as a naturalist. You would say no, of course. And that is just what Robert told his son - at first. Fortunately for Charles, Robert recognized that his son was becoming a man and had found a passion in life. Robert eventually allowed himself to become convinced, and he agreed to fund the excursion.

During the five-year voyage of the Beagle, Charles lived on the 90-foot long, 25-foot wide ship with over 70 other sailors. The ship also contained surveying equipment and enough supplies to last for several months at sea. For Charles it must have been a difficult transition from his life of ease, but he made the most of it. He spent his time at sea reading and studying. When the ship stopped at islands or at the South American mainland, he collected animals and sent them back to England on the next available ship. He collected a huge variety of species during his travels. Similar species on neighboring islands were different enough from one another that each seemed to have adapted to its own particular environment.

Charles returned home to England in 1836 at the age of 27. Almost immedi-ately after his return to England, he began working on his book Origin of Species [Darwin, 1859], which would end up being a decades-long project. He also was ac-tive in writing journal papers and speaking at conferences. He continued studying and learning as he began putting together a coherent theory of natural selection.

Natural selection says that the most fit individuals survive and pass on their char-acteristics to their offspring. This is how adaptation takes place - through the

"survival of the fittest."

As Charles continued working on his book, he was hesitant to publicize his theory of evolution. Having studied the ministry for three years, he knew that his theory could generate a storm of controversy because of its possible contradiction with the Bible. He wanted to build an air-tight case and a true magnum opus before publishing his results. However, in 1858 he received a paper from Alfred Wallace, a naturalist who was traveling in the South Pacific. Wallace had independently

arrived at many of the same ideas as Darwin, and sent a paper to Darwin asking for his help in publishing it.

Darwin was in somewhat of a predicament. He had a choice to make. He could

"lose" Wallace's paper,¹ publish his own results, and claim precedence for his theory of evolution. Or he could submit Wallace's paper for publication and allow Wallace to have precedence. To his credit, Darwin decided to try to strike a balance. He quickly wrote his own paper, and then presented both his and Wallace's paper at the next available conference. He then put the finishing touches on his book, which ended up being much shorter than he originally intended2 due to his haste to stake a claim to the credit that he deserved. The Origin of Species was published in 1859, and the first printing of 1,250 copies sold out in one day. Darwin was on the fast track to becoming the most famous and controversial scientist of his generation.

Although Darwin's theory of evolution quickly gained scientific credibility, like all new theories, it was not without detractors. First, it seemed to go against the Bible's teaching of the special creation of all species and thus was susceptible to attacks by religious leaders. Second, Darwin did not have any idea how traits were passed by parents to their offspring. In some ways it is surprising that his theory gained acceptance as quickly as it did in spite of his lack of explanation for heredity.

He observed that it happened and so he postulated natural selection, but he could not say how it happened.

Darwin, along with other scientists of his time, had two fundamental misconcep-tions about heredity. First, he believed that the traits of parents could be blended in their offspring; for example, the child of a black mouse and a white mouse might be gray. Second, he believed that acquired traits could be passed to offspring. For example, a man who lifts weights and becomes strong will tend to have strong children because of his weight lifting.

Darwin, a child of privilege, developed the theory of natural selection, but it would be left to a child of poverty, Gregor Mendel, to prove it.

3.1.2 Gregor Mendel

Gregor Mendel was the first to understand and explain how heredity occurs. He was born as Johann Mendel in 1822 to a poor farmer in Czechoslovakia [Bankston, 2005]. His father needed him to help on the farm, but young Johann was much more suited to academics than physical labor. His parents could barely afford it, but they sent him to school in order to help him gain the opportunities in life that they lacked. In spite of his parents' support and his own part-time work, he could barely survive financially as a student. His financial situation was much the same as many graduate students today, except that there were fewer opportunities for financial aid.

At the age of 21, Mendel heard about a nearby monastery where he could con-tinue his education without any financial worries. He would have to take a vow of poverty and celibacy, but the financial benefits were too good to turn down. Mendel

1Who would have doubted Darwin's claim that a letter mailed from the South Pacific to England in 1858 had never arrived?

2This all worked out for the best in the long run. Darwin's book was about 500 pages. If he had finished it the way he wanted to, it would have been several hundred pages longer and would have been more daunting to potential readers. By making the book shorter he increased his readership and subsequent success.

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was not particularly religious, but he jumped at the opportunity and joined the Au-gustinian order of the St. Thomas Monastery.

Augustine, who lived in the Roman empire around 400 AD, was one of the greatest intellectual leaders in Christian history. His theology emphasized the abil-ity of God to communicate to man through secular knowledge. The monastery that Mendel joined, in keeping with the philosophy of its namesake, encouraged learning in all areas of life and was thus a perfect fit for Mendel. It was "worldly" compared with many other monasteries. The monks did not have to punish themselves, or spend all day praying, or take vows of silence. They only had to study, believing that God spoke to them through their learning. In accordance with tradition, Jo-hann Mendel gave himself a new name when he joined St. Thomas; his name was now Gregor Mendel.

As a monk, Mendel continued to take classes at universities, taught science at nearby schools, read, and conducted his own research at the monastery. The research that he pursued involved the breeding of plants, and in particular, peas.

This was a fitting avenue for his creative talents because of his background on his father's farm.

As Mendel experimented with peas, he noticed that they had various traits. Some were smooth, while others were rough; some were more green, while others were more yellow; some had buds in one location, others had buds in another location.

As Mendel experimented, he realized that the traits were controlled by some unseen unit of heredity, which he called elements. Some of the elements were strong and tended to have more control over the peas' traits. Other elements were weak and had less control over the peas' traits. Today, we use the word gene instead of element, and we say that genes are either dominant or recessive, rather than strong or weak. But it was Mendel who first understood genetics, heredity, and dominance.

Mendel's work was the missing link in Darwin's theory, and explained how natural selection worked.

Mendel presented his findings at a conference in 1865. This was only six years after Darwin's publication of Origin of Species, but for some reason Mendel's au-dience did not realize the magnitude of what he had discovered. The reception of Mendel's scientific breakthrough could not have been more different than that of Darwin's. Whereas Darwin became immediately famous, Mendel's work was ig-nored. He continued to work in obscurity at St. Thomas, publishing a few papers here and there, all of which were essentially overlooked by the scientific community.

Mendel became the administrative leader of St. Thomas in 1868 and didn't have much time for science after that.³ Mendel died in 1884. His work on genetics was finally rediscovered by the Dutch biologist Hugo de Vries, the German botanist Carl Correns, and the Austrian agronomist Erich von Tschermak, all around 1900.