Evolution connection: proteins, carbohydrates, and nucleic acidsEvolution connection: proteins, carbohydrates, and nucleic acids

Learning goals:Students will understand that 1) our evolutionary history has affected our genes and proteins, 2) the availability of particular

carbohydrates in the environment has shaped the evolutionary history of different human populations, and 3) our evolutionary history

matters in our everyday lives.

For the instructor:This short slide set weaves together basic information about carbohydrates, proteins, and nucleic acids into one evolutionary story

that relates to students’ everyday lives. To integrate it best, use these slides immediately after you’ve discussed the structure of these

biological molecules. You may wish to prime students for this story by using lactose and lactase as examples when discussing

carbohydrates and proteins. Additional details about the translation of nucleic acids into proteins could be incorporated into the last

slide of this series, to the degree that you cover this material in your discussion of the structure of nucleic acids. You may also wish to

return to this story as an example when you cover Mendelian genetics. The European version of the lactase persistence gene is

inherited as a dominant Mendelian trait.

Each of the following slides comes with a sample script for the instructor.  To review this script, download the PowerPoint file and view

the Notes associated with each slide.

Evolution Connection slideshows are provided by Understanding Evolution (understandingevolution.org) and are copyright 2011 by

The University of California Museum of Paleontology, Berkeley, and the Regents of the University of California. Feel free to use and

modify this presentation for educational purposes.

Evolution connection: proteins, carbohydrates, and nucleic acidsEvolution connection: proteins, carbohydrates, and nucleic acids

Digesting lactose with an enzyme

Lactose

Galactose Glucose

Evolution connection: proteins, carbohydrates, and nucleic acidsEvolution connection: proteins, carbohydrates, and nucleic acids

Lactase to the rescue!

Galactose Glucose

Lactose

Lactase image is from BioMolecular Explorer 3D and is used under the conditions of a Creative

Commons Attribution-NonCommercial-ShareAlike 3.0 License.

Evolution connection: proteins, carbohydrates, and nucleic acidsEvolution connection: proteins, carbohydrates, and nucleic acids

Gene for

lactase

Evolution connection: proteins, carbohydrates, and nucleic acidsEvolution connection: proteins, carbohydrates, and nucleic acids

Photo of highland cattle is by the Scottish government and is used under the conditions of a Creative Commons

license. Photo of Masai with cattle is by Oxfam International and is used under the conditions of a Creative

Commons license.

Lactose tolerance

arises several times

and increases in

frequency.

Lactose tolerance

arises and increases

in frequency.

10,000 years ago:

100% lactose intolerant

10,000 years ago:

100% lactose intolerant

Milkshake photo by Svadilfari and used under a Creative Commons license.

1. Ancestral lactose

control gene on

chromosome 2

lactose intolerance

2. C nucleotide replaced

by a T nucleotide

lactose tolerance

3. One of three single

nucleotide changes

lactose tolerance

Evolution connection: proteins, carbohydrates, and nucleic acidsEvolution connection: proteins, carbohydrates, and nucleic acids

Reference:Reference:

Tishkoff, S. A., Reed, F. A., Ranciaro, A., Voight, B. F., Babbitt, C. C., Silverman, J. S.

. . . Deloukas, P. (2006). Convergent adaptation of human lactase persistence in

Africa and Europe. Nature Genetics. 39: 31-10.

Evolution Connection slideshows are provided by Understanding Evolution

(understandingevolution.org) and are copyright 2011 by The University of California Museum of

Paleontology, Berkeley, and the Regents of the University of California. Feel free to use and

modify this presentation for educational purposes.