A locus for familial hypertrophic cardiomyopathy is closely linked to the cardiac myosin heavy chain genes, CRI-L436, and CRI-L329 on chromosome 14 at q11-q12

We report that a gene responsible for familial hypertrophic cardiomyopathy (HC) is closely linked to the cardiac alpha and beta myosin heavy chain (MHC) genes on chromosome 14q11. We have recently shown that probe CRI-L436, derived from the anonymous DNA locus D14S26, detects a polymorphic restriction fragment that segregates with familial HC in affected members of a large Canadian family. Using chromosomal in situ hybridization, we have mapped CRI-L436 to chromosome 14 at q11-q12. Because the cardiac MHC genes also map to this chromosomal band, we have determined the genetic distances between the cardiac beta MHC gene, D14S26, and the familial HC locus. Data presented here show that these three loci are linked within 5 centimorgans on chromosome 14 at q11-q12. The possibility that defects in either the cardiac alpha or beta MHC genes are responsible for familial HC is discussed.     

Localization of human variable and constant region immunoglobulin heavy chain genes on subtelomeric band q32 of chromosome 14

Analysis of a group of human/rodent somatic cell hybrids with nucleic acid probes prepared from cloned human variable region (VH), junctional (JH), and constant region (C epsilon) heavy chain immunoglobulin genes indicates that all of these IgH genes are localized on the subtelomeric (q32) band of chromosome 14. Somatic cell hybrids were isolated in selective medium after fusing human fibroblasts with hprt- Chinese hamster cells. The human parental cells contained two translocation chromosomes representing a reciprocal translocation between chromosomes X and 14. Only those hybrid cell lines retaining a complete human autosome 14 or the X/14 translocation chromosome (i.e. containing band 14q32) retained the human IgH genes. Retention of these genes did not correlate with the presence of the other translocation chromosome, 14/X. These results indicate that all human IgH genes (VH, JH, and CH) map to the same chromosomal band (14q32) which is commonly involved in reciprocal translocations with human chromosome 8 (8q24) in B-cell neoplasms.     

Influence of the estrous cycle on heterosexual aggression in two strains of rats (S3 and WEzob)

Two strains of rats (S₃ and WEzob), which show different levels of aggression in the laboratory, were tested in repeated heterosexual confrontations. Daily 15-min observations were made of the interactions between a female throughout a complete estrous cycle and the same male partner. In both strains the topography of aggression was similar in males and females, but the frequency of specific parameters varied. Males showed more offensive and females more defensive patterns. The overall level of aggression was very low on the day of estrous, when the female was sexually receptive. There were no differences in any elements of female or male behavior between the other 3 days of the cycle. The results support previous conclusions from single-sex encounters that in rats there is no sexual dimorphism in the ability to show aggression.     

Contents of several amino acids in the cerebellum, brain stem and cerebrum of the 'staggerer', 'weaver' and 'nervous' neurologically mutant mice.

The content of glutamate, GABA, aspartate, glycine and alanine was determined in the cerebellum, brain stem and cerebrum of three different mutant mice which have been named ‘staggerer’, ‘weaver’ and ‘nervous’ on the basis of neurological symptoms. In the ‘staggerer’ and ‘weaver’ mutants there is an almost complete absence of granule cells in the cerebellar cortex while in the ‘nervous’ mutant there is a loss of Purkinje cells (and to a lesser extent a loss of granule cells) in the cerebellar cortex. In the cerebellum of the ‘weaver’ mutant, the content of glutamate was signficantly lower (P < 0.025) than control values (8.77 ± 0.76 vs 12.0 ± 1.3 μmol/g tissue wet wt) and the contents of GABA and glycine were significantly greater than normal levels. In the cerebellum of the ‘staggerer’ mutant, the content of glutamate was significantly lower (6.62 ± 0.70 μmol/g) and the contents of glycine and alanine significantly higher than control values. In the cerebrum and brain stem regions of the staggerer mutant, weaver mutant and the normals the contents of the five amino acids were the same. The contents of glycine and alanine in the cerebellum, GARA and glycine in the brain stem and GABA and alanine in the cerebrum of the nervous mutants were higher than control values. The data are discussed in terms of a possible role for glutamate functioning as an excitatory transmitter when released from the cerebellar granule cells.     

The cultural evolution of fertility decline

Cultural evolutionists have long been interested in the problem of why fertility declines as populations develop. By outlining plausible mechanistic links between individual decision-making, information flow in populations and competition between groups, models of cultural evolution offer a novel and powerful approach for integrating multiple levels of explanation of fertility transitions. However, only a modest number of models have been published. Their assumptions often differ from those in other evolutionary approaches to social behaviour, but their empirical predictions are often similar. Here I offer the first overview of cultural evolutionary research on demographic transition, critically compare it with approaches taken by other evolutionary researchers, identify gaps and overlaps, and highlight parallel debates in demography. I suggest that researchers divide their labour between three distinct phases of fertility decline—the origin, spread and maintenance of low fertility—each of which may be driven by different causal processes, at different scales, requiring different theoretical and empirical tools. A comparative, multi-level and mechanistic framework is essential for elucidating both the evolved aspects of our psychology that govern reproductive decision-making, and the social, ecological and cultural contingencies that precipitate and sustain fertility decline.