MHC odours are not required or sufficient for recognition of individual scent owners

To provide information about specific depositors, scent marks need to encode a stable signal of individual ownership. The highly polymorphic major histocompatibility complex (MHC) influences scents and contributes to the recognition of close kin and avoidance of inbreeding when MHC haplotypes are shared. MHC diversity between individuals has also been proposed as a primary source of scents used in individual recognition. We tested this in the context of scent owner recognition among male mice, which scent mark their territories and countermark scents from other males. We examined responses towards urine scent according to the scent owner's genetic difference to the territory owner (MHC, genetic background, both and neither) or genetic match to a familiar neighbour. While urine of a different genetic background from the subject always stimulated greater scent marking than own, regardless of familiarity, MHC-associated odours were neither necessary nor sufficient for scent owner recognition and failed to stimulate countermarking. Urine of a different MHC type to the subject stimulated increased investigation only when this matched both the MHC and genetic background of a familiar neighbour. We propose an associative model of scent owner recognition in which volatile scent profiles, contributed by both fixed genetic and varying non-genetic factors, are learnt in association with a stable involatile ownership signal provided by other highly polymorphic urine components

Effect of late familiarization on human mating preferences

Male and female students were asked to select from groups of photographs projected on slides the individual preferred as a mate in a long‐term husband‐wife relationship. The students were later shown some of the same photographs several times to familiarize them with these individuals. The students were subsequently shown the same groups of photographs from which they initially indicated mating preferences and were again asked to indicate their preferences. When familiarization immediately preceded the final preference selections, both male and female students switched preferences and chose individuals with whom they had been familiarized approximately twice as often as they switched preferences and chose individuals with whom they had not been familiarized. When familiarization preceded the final preference selection by seven days, the frequency of switching and choosing the familiar type did not increase. These results and the possible evolutionary basis for the results are discussed

Sociobiologia possibile. Neodarwinismo e scienze dell'uomo: la ricerca di un'alternativa al determinismo biologico

Un confronto interdisciplinare sulla sociobiologia che cerca di individuare una strada per un confronto costruttivo fra evoluzionismo e scienze sociali oltre il determinismo di molte formulazioni

Developmental plasticity and human health

Many plants and animals are capable of developing in a variety of ways, forming characteristics that are well adapted to the environments in which they are likely to live. In adverse circumstances, for example, small size and slow metabolism can facilitate survival, whereas larger size and more rapid metabolism have advantages for reproductive success when resources are more abundant. Often these characteristics are induced in early life or are even set by cues to which their parents or grandparents were exposed. Individuals developmentally adapted to one environment may, however, be at risk when exposed to another when they are older. The biological evidence may be relevant to the understanding of human development and susceptibility to disease. As the nutritional state of many human mothers has improved around the world, the characteristics of their offspring—such as body size and metabolism—have also changed. Responsiveness to their mothers' condition before birth may generally prepare individuals so that they are best suited to the environment forecast by cues available in early life. Paradoxically, however, rapid improvements in nutrition and other environmental conditions may have damaging effects on the health of those people whose parents and grandparents lived in impoverished conditions. A fuller understanding of patterns of human plasticity in response to early nutrition and other environmental factors will have implications for the administration of public health