LETTERS 



The Deep Roots 

 of Altruism 



Joan E. Strassmann and 

 David C. Queller's article 

 "Altruism among Amoe- 

 bas" [9/07] provides a 

 fascinating account of the 

 operation of altruism in 

 both social amoebas and 

 the human "dicty com- 

 munity." But I have a res- 

 ervation: in paragraph two 

 we are told that we should 

 expect to find the roots of 

 human altruism "deeper 

 in nature"; in the penul- 

 timate paragraph, which 

 returns to humans, we 

 learn that human coop- 

 eration "often depends on 

 reciprocation." Embedded 

 within a discussion of spe- 

 cific genetic mechanisms, 

 these statements may leave 



the impression that the 

 mechanisms described in 

 the article apply to us to 

 some degree. Although 

 human altruism likely 

 has a genetic basis, I am 

 reasonably confident that 

 the mechanism(s) does not 

 involve the dimA or csaA 

 genes. Because of this, 

 Dictyostelium discoideum has 

 no direct bearing on the 

 "roots" of our own version 

 of altruism. The research 

 on amoebas supports the 

 idea that altruism in hu- 

 mans has a genetic basis. 

 However, the support is 

 analogical, not functional. 

 James J. Moore 

 Department of Anthropology 

 I diversity of California, 

 San Diego 

 La Jolla, California 



David C. Queller re- 

 plies: We agree that hu- 

 man altruism is unlikely 

 to involve the same genes 

 that we study in social 

 amoebas. Indeed, many 

 of those genes are absent 

 from the human genome. 

 We are trying to under- 

 stand the general princi- 

 ples by which social genes 

 evolve, principles that may 

 eventually be shown to 

 operate in humans. For 

 example, it is likely that 

 kin selection is involved 

 in human altruism. We 

 would be surprised if the 

 insight from dimA — that 

 social genes can reduce 

 cheating by piggybacking 

 on other essential func- 

 tions — does not apply to 

 other genes in other spe- 



cies. The human genome 

 might include so-called 

 greenbeard genes — which 

 enable altruism toward 

 others who carry them — 

 now that they have moved 

 from hypothesis to reality, 

 as in the case of csaA. 



Dark Matters 



I was intrigued by Donald 

 Goldsmith's article "Dark 

 Matter" [9/07], as I have 

 been by all I have read 

 on dark matter and dark 

 energy. While I am not a 

 physicist or a cosmologist, 

 I can't help but wonder 

 if there might not be yet 

 another explanation for 

 this extraordinary finding. 

 We ask what there was 

 before the big bang. Is it 

 not possible that this non- 



