Enard, W., Przeworski, M., Fisher, S. E., Lai, C. S. L., Wiebe, V., Kitano, T., Monaco, A. P., & Paabo, S. (2002). Molecular evolution of FOXP2, a gene involved in speech and language. Nature, 418(6900), 869-872.
Language is a uniquely human trait likely to have been a prerequisite for the development of human culture. The ability to develop articulate speech relies on capabilities, such as fine control of the larynx and mouth(1), that are absent in chimpanzees and other great apes. FOXP2 is the first gene relevant to the human ability to develop language(2). A point mutation in FOXP2 co-segregates with a disorder in a family in which half of the members have severe articulation difficulties accompanied by linguistic and grammatical impairment(3). This gene is disrupted by translocation in an unrelated individual who has a similar disorder. Thus, two functional copies of FOXP2 seem to be required for acquisition of normal spoken language. We sequenced the complementary DNAs that encode the FOXP2 protein in the chimpanzee, gorilla, orang-utan, rhesus macaque and mouse, and compared them with the human cDNA. We also investigated intraspecific variation of the human FOXP2 gene. Here we show that human FOXP2 contains changes in amino- acid coding and a pattern of nucleotide polymorphism, which strongly suggest that this gene has been the target of selection during recent human evolution.
[not in handout, see intranet]
Johnston, T. D., & Edwards, L. (2002). Genes, interactions, and the development of behavior. Psychological Review, 109(1), 26-34.
Explaining how genes influence behavior is important to many branches of psychology, including development, behavior genetics, and evolutionary psychology. Presented here is a developmental model linking the immediate consequence of gene activity (transcription of messenger RNA molecules from DNA sequences) to behavior through multiple molecular, cellular, and physiological levels. The model provides a level of detail appropriate to theories of behavioral development that recognizes the molecular level of gene action, dispensing with the metaphorical use of such terms as blueprints, plans, or constraints that has obscured much previous discussion. Special attention is paid to the possible role of immediate-early genes in initiating developmental responses to experience, adding specificity to the claim that neither genes nor experience act alone to shape development.
Kullberg, C., & Lind, J. (2002). An experimental study of predator recognition in great tit fledglings. Ethology, 108(5), 429-441.
Studies of naturally predator-naive adult birds (finches on predator- free islands) and birds experimentally hand reared in isolation from predators indicate that birds can recognise predators innately; that is, birds show anti-predator behaviour without former experience of predators. To reduce predation risk efficiently during the vulnerable fledgling period, we would predict an innate response to be fully developed when the chicks leave the nest. However, 30-day-old naive great tit fledglings (Parus major) did not respond differently to a model of a perched predator than to a similarly sized model of a non- predator. Although chicks showed distress responses such as warning calls and freezing behaviour, they did not differentiate between the stimuli. In contrast, wild-caught first-year birds (4 mo old) and adults responded differentially to the two stimuli. Lack of recognition of a perched predator might be one explanation for the high mortality rate found in newly fledged great tits. Our results imply that parental care is not only important for food provisioning, but also to reduce predation risk during the time when fledglings are most vulnerable.
Lai, C. S. L., Fisher, S. E., Hurst, J. A., Vargha- Khadem, F., & Monaco, A. P. (2001). A forkhead-domain gene is mutated in a severe speech and language disorder. Nature, 413(6855), 519- 523.
Individuals affected with developmental disorders of speech and language have substantial difficulty acquiring expressive and/or receptive language in the absence of any profound sensory or neurological impairment and despite adequate intelligence and opportunity(1). Although studies of twins consistently indicate that a significant genetic component is involved(1-3), most families segregating speech and language deficits show complex patterns of inheritance, and a gene that predisposes individuals to such disorders has not been identified. We have studied a unique three- generation pedigree, KE, in which a severe speech and language disorder is transmitted as an autosomal-dominant monogenic trait(4). Our previous work mapped the locus responsible, SPCH1, to a 5.6-cM interval of region 7q31 on chromosome 7 (ref. 5). We also identified an unrelated individual, CS, in whom speech and language impairment is associated with a chromosomal translocation involving the SPCH1 interval(6). Here we show that the gene FOXP2, which encodes a putative transcription factor containing a polyglutamine tract and a forkhead DNA- binding domain, is directly disrupted by the translocation breakpoint in CS. In addition, we identify a point mutation in affected members of the KE family that alters an invariant amino-acid residue in the forkhead domain. Our findings suggest that FOXP2 is involved in the developmental process that culminates in speech and language.
Meaburn, E., Dale, P. S., Craig, I. W., & Plomin, R. (2002). Language-impaired children: No sign of the FOXP2 mutation. Neuroreport, 13(8), 1075-1077.
A mutation in the FOXP2 gene has been found to be responsible for the autosomal dominant inheritance of a severe form of speech and language! impairment in a family known as KE. We genotyped the FOXP2 mutation for 270 4-year-old children selected for low general language scores from a representative community sample of more than 18,000 children. No language- impaired child had the FOXP2 mutation. Although rare severe disorders such as those of the KE family are often caused by a single gene, common disorders such as language impairment are more likely to be the quantitative extreme of the same multiple genetic factors responsible for heritability throughout the distribution.
Newbury, D. F., Bonora, E., Lamb, J. A., Fisher, S. E., Lai, C. S. L., Baird, G., Jannoun, L., Slonims, V., Stott, C. M., Merricks, M. J., Bolton, P. F., Bailey, A. J., & Monaco, A. P. (2002). FOXP2 is not a major susceptibility gene for autism or specific language impairment. American Journal of Human Genetics, 70(5), 1318-1327.
The FOXP2 gene, located on human 7q31 (at the SPCH1 locus), encodes a transcription factor containing a polyglutamine tract and a forkhead domain. FOXP2 is mutated in a severe monogenic form of speech and language impairment, segregating within a single large pedigree, and is also disrupted by a translocation in an isolated case. Several studies of autistic disorder have demonstrated linkage to a similar region of 7q (the AUTS1 locus), leading to the proposal that a single genetic factor on 7q31 contributes to both autism and language disorders. In the present study, we directly evaluate the impact of the FOXP2 gene with regard to both complex language impairments and autism, through use of association and mutation screening analyses. We conclude that coding-region variants in FOXP2 do not underlie the AUTS1 linkage and that the gene is unlikely to play a role in autism or more common forms of language impairment.
Rankin, C. H. (2002). From gene to identified neuron to behaviour in Caenorhabditis elegans. Nature Reviews Genetics, 3(8), 622-630.
Understanding the role of genes in behaviour is greatly enhanced by understanding how they affect the function of the neurons that underlie behaviour. The study of behavioural genetics in Caenorhabditis elegans, an organism with a nervous system small enough to allow the role of every neuron in a given behaviour to be known, has given researchers unique insights into how genes contribute to behaviour in general. Many have taken advantage of the unique features of this worm to analyse genes from their sequence to their role in neuronal function and, ultimately, in behaviour.
Sewards, T. V., & Sewards, M. A. (2002). Innate visual object recognition in vertebrates: some proposed pathways and mechanisms. Comparative Biochemistry and Physiology a-Molecular and Integrative Physiology, 132(4), 861-891.
Almost all vertebrates are capable of recognizing biologically relevant stimuli at or shortly after birth, and in some phylogenetically ancient species visual object recognition is exclusively innate. Extensive and detailed studies of the anuran visual system have resulted in the determination of the neural structures and pathways involved in innate prey and predator recognition in these species [Behav. Brain Sci. 10 (1987) 337; Comp. Biochem. Physiol. A 128 (2001) 417]. The structures involved include the optic tectum, pretectal nuclei and an area within the mesencephalic tegmentum. Here we investigate the structures and pathways involved in innate stimulus recognition in avian, rodent and primate species. We discuss innate stimulus preferences in maternal imprinting in chicks and argue that these preferences are due to innate visual recognition of conspecifics, entirely mediated by subtelencephalic structures. In rodent species, brainstem structures largely homologous to the components of the anuran subcortical visual system mediate innate visual object recognition. The primary components of the mammalian subcortical visual system are the superior colliculus, nucleus of the optic tract, anterior and posterior pretectal nuclei, nucleus of the posterior commissure, and an area within the mesopontine reticular formation that includes parts of the cuneiform, subcuneiform and pedunculopontine nuclei. We argue that in rodent species the innate sensory recognition systems function throughout ontogeny, acting in parallel with cortical sensory and recognition systems. In primates the structures involved in innate stimulus recognition are essentially the same as those in rodents, but overt innate recognition is only present in very early ontogeny, and after a transition period gives way to learned object recognition mediated by cortical structures. After the transition period, primate subcortical sensory systems still function to provide implicit innate stimulus recognition, and this recognition can still generate orienting, neuroendocrine and emotional responses to biologically relevant stimuli. (C) 2002 Elsevier Science Inc. All rights reserved.
Sugiyama, L. S., Tooby, J., & Cosmides, L. (2002). Cross-cultural evidence of cognitive adaptations for social exchange among the Shiwiar of Ecuadorian Amazonia. PNAS, 99(17), 11537- 11542.
On the basis of evolutionary game theory, it was hypothesized that humans have an evolved cognitive specialization for reasoning about social exchange, including a subroutine for detecting cheaters. This hypothesis led to a specific prediction: Although humans are known to be poor at detecting potential violations of conditional rules in general, they should nevertheless detect them easily when the rule involves social exchange and looking for violations corresponds to looking for cheaters. This prediction was subsequently confirmed by numerous tests. Evolutionary analyses further predict that: (i) in humans, complex adaptations will be distributed in a species-typical fashion; and (ii) aspects of cognitive organization relevant to performing the evolved function of an adaptation should be more buffered against environmental and cultural variation than function- irrelevant aspects. Here we report experiments testing whether social exchange reasoning exhibits these properties of adaptations. Existing tests of conditional reasoning were adapted for nonliterate experimental subjects and were administered to Shiwiar hunter- horticulturalists of the Ecuadorian Amazon. As predicted, Shiwiar subjects were as highly proficient at cheater detection as subjects from developed nations. Indeed, the frequency of cheater-relevant choices among Shiwiar hunter-horticulturalists was indistinguishable from that of Harvard undergraduates. Also as predicted, cultural variation was confined to those aspects of reasoning that are irrelevant to social exchange algorithms functioning as an evolutionarily stable strategy. Finally, Shiwiar subjects displayed the same low performance on descriptive conditionals as subjects from developed nations. Taken together, these findings support the hypotheses that social exchange algorithms are species-typical and that their evolutionarily stable strategy (ESS)-relevant subroutines are developmentally buffered against cultural variation.
Tsai, K. J., Chen, S. K., Ma, Y. L., Hsu, W. L., & Lee, E. H. Y. (2002). sgk, a primary glucocortcoid-induced gene, facilitates memory consolidation of spatial learning in rats. Proceedings of the National Academy of Sciences of the United States of America, 99(6), 3990-3995.
By using differential display PCR, we have identified 98 cDNA fragments from the rat dorsal hippocampus that are expressed differentially between the fast learners and slow learners in the water maze learning task. One of these cDNA fragments encodes the rat serum- and glucocorticoid-inducible kinase (sgk) gene. Northern blot analysis revealed that the sgk mRNA level was approximately 4-fold higher in the hippocampus of fast learners than slow learners. In situ hybridization results indicated that sgk mRNA level was increased markedly in CA1, CA3, and dentate gyrus of hippocampus in fast learners. Transient transfection of the sgk mutant DNA to the CA1 area impaired, whereas transfection of the sgk wild-type DNA facilitated water maze performance in rats. These results provide direct evidence that enhanced sgk expression facilitates memory consolidation of spatial learning in rats. These results also elucidate the molecular mechanism of glucocorticoid-induced memory facilitation in mammals.
Zhao, J., & Li, D. F. (2002). Vocal learning and memory in songbird are related to immediate early genes. Progress in Biochemistry and Biophysics, 29(2), 173-176.
On the basis of the recent reports, immediate early gene (IEG) can be rapidly induced and expressed when a songbird is either stimulated by bird-song or in its vocal-behavior. The expression area and level in brain of IEG, such as zenk, c-fos and c-jun, are corresponding to where the neurons are related, as a songbird is stimulated, suggesting that IEG plays an important role in vocal learning and memory.