Sir—In his News and Views article on chiral morphology (Nature 330, 204-205; 1987), John Galloway makes an error in terminology that is frequently committed: the confusion of ‘maternal inheritance’ with ‘maternal effect’. He describes as an example of maternal inheritance the case in which “the hand of coiling is determined not by the individual snail’s own genes but by those of its mother”. This should have been described as a maternal effect. Maternal inheritance (King, R. C. & Stansfield, W.D. A Dictionary of Genetics; Oxford University Press, 1985), in contrast, is when a particular genetic element is transmitted only through the mother — as with mitochondria, for example. An example of paternal inheritance is the transmission of the Y chromosome in mammals. I can think of no simple example of ‘paternal effect’, unless one would allow sporophytic self-incompatibility, in which the genotype of the anther determines the compatibility phenotype of the pollen, regardless of the pollen’s haplotype. Because the physiological, genetic and evolutionary aspects of these features of heredity are quite distinct, the distinctions between them should be clearly understood.
LEE ALTENBERG Department of Zoology, Duke University,
Durham, North Carolina 27706, USA