Jumping Gene Darkened Moths: Genetics of Classic Example of Natural Selection Explained

By Saey, Tina Hesman | Science News, June 25, 2016 | Go to article overview

Jumping Gene Darkened Moths: Genetics of Classic Example of Natural Selection Explained


Saey, Tina Hesman, Science News


Peppered moths and some copycat butterflies owe their color changes to a single gene, two new studies suggest.

A tweak in a portion of the cortex gene painted the speckled gray wings of peppered moths black, researchers report in the June 2 Nature. Genetic variants in DNA interspersed with and surrounding the cortex gene also helped some tasty species of Heliconius butterfly mimic unpalatable species, a second team of scientists reports, also in Nature.

In the often-told evolutionary tale, the peppered moths' color shift began as factories in Britain darkened the skies and trees with smoke during the Industrial Revolution in the 1800s. Naturalists took note as a new, all-black carbonaria form of peppered moths (Biston betularia) blended into sooty backgrounds; the light-colored typica moths were easily picked off by birds. By 1970, nearly 99 percent of peppered moths were black in some localities. As air pollution decreased in the late 20th century, black moths became more visible to birds. Now, carbonaria moths are rare.

The new research "begins to unravel exactly what the original mutation was that produced the black ... moths that were favored by natural selection" during much of the last century, says evolutionary biologist Paul Brakefield of the University of Cambridge. "It adds a new and exciting element to the story."

The molecular details behind the wing pattern changes have eluded scientists for decades. In 2011, researchers tracked the traits to a region of a chromosome that the moths and butterflies share (SN: 9/24/11, p. 16; SN: 5/7/11, p. 11). Which of the many genes in that region might be responsible remained a mystery.

In peppered moths, the region of interest stretches over about 400,000 DNA bases and contains 13 genes and two microRNAs. "There aren't really any genes that scream out to you, 'I'm involved in wing patterning,'" says evolutionary geneticist Ilik Saccheri of the University of Liverpool in England.

Saccheri and colleagues compared that region in one black moth and three typical moths. The black moth differed from the light-colored moths in 87 places. Most of the differences were changes in just one or a few DNA bases--the information-carrying chemicals in DNA. One difference was the insertion of a 21,925-base-long stretch of DNA into the region. This big chunk contained multiple copies of a transposable element, or jumping gene. Transposable elements are viruslike pieces of DNA that copy and insert themselves into a host's DNA.

By examining the DNA of hundreds more typica moths and ruling out mutations one by one, the team ended up with one candidate: the large transposable element, which had landed in the cortex gene. …

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Note: primary sources have slightly different requirements for citation. Please see these guidelines for more information.

Cited article

Jumping Gene Darkened Moths: Genetics of Classic Example of Natural Selection Explained
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen
Items saved from this article
  • Highlights & Notes
  • Citations
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Search by... Author
    Show... All Results Primary Sources Peer-reviewed

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.