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Harrison Echols

Harrison Echols is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Harrison Echols rather than just read about it. In short: Gessner Harrison "Hatch" Echols Jr. (May 1, 1933 – April 11, 1993) was an American molecular biologist, biochemist, and geneticist, whose work on the lambda phage advanced the understanding of viral infections and gene regulation inside the cell.

Key takeaways

  • Harrison Echols belongs to biology; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Harrison Echols to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Harrison Echols from memory before moving on to harder problems.

Reference excerpt

Gessner Harrison "Hatch" Echols Jr. (May 1, 1933 – April 11, 1993) was an American molecular biologist, biochemist, and geneticist, whose work on the lambda phage advanced the understanding of viral infections and gene regulation inside the cell.

Early life and education Harrison Echols was born in Charlottesville, Virginia in 1933, and attended the Episcopal High School in Alexandria, Virginia. He graduated in 1955 from the University of Virginia, where his grandfather William Holding Echols had been an influential professor of mathematics. He had initially intended to become a writer but ultimately completed his BA, MA, and PhD in physics. He earned his PhD in 1959 from the University of Wisconsin, Madison, where he would subsequently return as a professor the following year.

Research and career In 1959, Echols was first introduced to genetics as a postdoctoral student at Cyrus Levinthal's lab at MIT, where he uncovered the mechanism of regulation of the bacterial enzyme alkaline phosphatase. In contrast to Francois Jacob and Jacques Monod's 1960 operon theory that prescribed a single repressor model for regulation, Echols discovered that there were two separate genes acting on the enzyme: one positively (to promote) and one negatively (to repress). After completing his postdoctoral work, he returned to the University of Wisconsin, Madison as professor of biochemistry, where he taught from 1960 to 1969. He spent the remainder of his life as a professor of molecular biology at the University of California, Berkeley, from 1969 to 1993, chairing the department of molecular biology from 1978 to 1980. Echols was an early pioneer in scientific ethics, teaching courses on the subject long before it was common practice. In 1970 at a Phage Group meeting, he laid out a proposal for a more collaborative approach to science, wherein each paper in a given field would be coauthored by all scientists working in that field, so that scientific publications would better reflect the communal nature of science.

Areas of study At the University of Wisconsin, Echols began to study the lambda phage – in particular, the regulatory processes that determined when the phage would follow the lytic cycle or lysogenic cycle based on its conditions, continuing the work on gene regulation that he had begun with his study of alkaline phosphatase at MIT. Echols also performed pioneering work in determining how phage DNA moves in and out of a host cell's DNA during infection. According to Randy Schekman, "these studies were influential in suggesting how certain human tumor viruses may combine with a cell's chromosome." Later in his career, Echols became interested in factors controlling fidelity of DNA replication and the SOS response caused by DNA damage. He spent a sabbatical year in 1981–1982 in Arthur Kornberg's group at Stanford University, where he gained experience with the then-novel approaches of enzymology and electron microscopy. Using his broad palette of techniques, he wrote a number of papers of "virtuosic science" starting in 1982 studying DNA polymerase III and SOS mutagenesis.

Honors In 1981, Echols was awarded the Guggenheim Fellowship. In 1991, he was elected a Member of the National Academy of Sciences.

Personal life Echols was married four times, and at the time of his death was married to cell biologist Carol Gross. He had four children with his first wife, Jean Crutchfield (m. 1954): Cathy, Elizabeth, Jean, and Robert. Echols was an accomplished tennis player. He played tennis at University of Virginia and won multiple trophies at a Madison, Wisconsin tournament in 1961. Mark Ptashne recounts a tennis match against Echols:

"Hatch presented himself as the archetypal Californian: tie-dyed shirt, hair in a ponytail, hesitant of speech—in short, way laid-back. At a Gordon Conference, I fell for this ruse and found myself on a tennis court with him. Hatch's demeanor didn't change much, but the balls came over the net with lethal speed and precision. It was something like being a civilian taking a stroll through Jurassic Park. I took up golf." – Mark Ptashne The Hatch Echols Memorial Tennis Tournament is held in his honor every year at the Molecular Genetics of Bacteria and Phages Meeting at the University of Wisconsin, Madison. Echols died of lung cancer on April 11, 1993, in Berkeley, California.

Selected works Operators and Promoters: The Story of Molecular Biology and Its Creators (written 1986–1992, published 2001), a narrative history of molecular biology, edited by Carol Gross after Echols's death and published posthumously

References

Worked examples

Example 1 — a first encounter with Harrison Echols

Start with the simplest possible case. Write down what Harrison Echols claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Harrison Echols before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Harrison Echols ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Harrison Echols

In research
Harrison Echols appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Harrison Echols in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Harrison Echols is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1933 births, 1993 deaths, 20th-century American biochemists, so understanding it makes those chapters shorter.
In everyday life
Look for Harrison Echols outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Harrison Echols in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Harrison Echols means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Harrison Echols out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Harrison Echols in simple terms?

Gessner Harrison "Hatch" Echols Jr. (May 1, 1933 – April 11, 1993) was an American molecular biologist, biochemist, and geneticist, whose work on the lambda phage advanced the understanding of viral infections and gene regulation inside the cell.

Why does Harrison Echols matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Harrison Echols?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Harrison Echols.

Tags

  • 1933 births
  • 1993 deaths
  • 20th-century American biochemists
  • American cell biologists
  • American geneticists
  • American molecular biologists
  • Episcopal High School (Alexandria, Virginia) alumni
  • Members of the United States National Academy of Sciences
  • Phage workers
  • University of California, Berkeley faculty
  • University of Wisconsin–Madison faculty

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