Behavior Genetics, Vol. 7, No. 1, 1977

LETTER TO THE EDITOR

Reply to Professor Lewontin's Letter 1

Trevor W i l l i a m s ~

Received 13 Feb. 1976

Few will find the scientific substance of Professor Lewontin 's observations a revelation. The " p r o b l e m " of correlated environments is discussed thoroughly in the literature, where it is seen to be something less than a problem (except in the case of sibs reared together). Falconer (1960, p. 161), for one, is prepared to disregard this as a component of the covariance between relatives (other than sibs) and to see the simplification as "no t entirely unrealistic." Moreover , Jinks and Fulker (1970) provide evidence in support of this view where the trait under examinat ion is IQ, as it is here. Thus, it seems clear that the literature alone provides suppor t for the esti- mat ion of heritabilities in this way. However, there is an additional source of support as well. The short paper in question is based on a larger project designed to address the issue of correlated environments directly. Prel iminary findings to be published this year indicate that very little of the resemblance between parents and offspring in these families can be attr ibuted to c o m m o n environments.

Given that Professor Lewont in is as familiar with this literature as anyone else in the field, one begins to wonder why he has been provoked into print once again. Whatever , most readers will see the reported heritabilities for what they are: modest estimates that may be modestly biased but, in Falconer ' s words, "no t entirely unrealistic." To equate them with random numbers verges on the absurd.

R E F E R E N C E S

Falconer, D. S. (1960). Introduction to Quantitative Genetics, Ronald Press, New York. Jinks, J. L., and Fulker, D. W. (1970). Comparisons of biometrical, genetical, MAVA, and

classical approaches to the analysis of human behavior. Psychol. Bull. 73:311-349.

1 R. C. Lewontin's letter to the Editor appeared in Behavior Genetics 6:373-374. Department of Sociology, The Australian National University, Canberra, Australia.

37 �9 1977 Plenum Publishing Corporation, 227 West 17tb Street, New York, N.Y. 10011. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission of the publisher.