May 24, 1997
"A Fantastical Experiment" (SN: 4/5/97, p. 214) taught me much about how cloning is done with higher animals. I was disturbed that there was nary a mention of plants, however.
People have been cloning plants for millennia, and botanists have long known that virtually all plant cells are totipotent. To suggest that "cloning is not really a scientific word" and that nuclear transplantation "is what most scientists refer to as cloning" is absurd. Zoologists may think that, provided they are ignorant of plant science, but botanists have long used the word in a perfectly scientific way and with no reference to nuclear transplantation.
The Random House dictionary defines a clone as "a population of [genetically] identical units, cells, or individuals that is derived from the same ancestral line" by asexual reproduction. A clone can consist of a single individual, but populations are more common.
For example, all the navel orange trees in Southern California form a clone; they are derived from the parent navel orange tree still growing in Riverside. Identical twins are a clone formed from a single fertilized egg.
Frank B. Salisbury
Professor of Plant Physiology
Utah State University
Logan, Utah
Cellular rejuvenation will lead ultimately to the rejuvenation of specialized adult cells. Nearing age 50, I could use some totipotency.
David Govett
Davis, Calif.
In "The shell in the soap" (SN: 3/22/97, p. 181), Hap Wheeler is quoted as saying, "Hundreds of millions of tons of [nondegradable commercial polymers] find their way into household products every year."
If that represents U.S. use, it requires a per capita consumption of about 1 ton of detergent. In my household, we use only 1.5 percent of that amount. If the figure represents worldwide household use, it implies that every person on the planet uses three times more detergent and cleaning products than we do.
David Thomas
Seattle, Wash.
Wheeler indeed said pounds, not tons, but points out that this global estimate is very conservative. -- C. Mlot
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Table of Contents -- May 24, 1997
