Heritability and social brood effects on personality in juvenile and adult life-history stages in a wild passerine.

How has evolution led to the variation in behavioural phenotypes (personalities) in a population? Knowledge of whether personality is heritable, and to what degree it is influenced by the social environment, is crucial to understanding its evolutionary significance, yet few estimates are available from natural populations. We tracked three behavioural traits during different life-history stages in a pedigreed population of wild house sparrows. Using a quantitative genetic approach, we demonstrated heritability in adult exploration, and in nestling activity after accounting for fixed effects, but not in adult boldness. We did not detect maternal effects on any traits, but we did detect a social brood effect on nestling activity. Boldness, exploration and nestling activity in this population did not form a behavioural syndrome, suggesting that selection could act independently on these behavioural traits in this species, although we found no consistent support for phenotypic selection on these traits. Our work shows that repeatable behaviours can vary in their heritability and that social context influences personality traits. Future efforts could separate whether personality traits differ in heritability because they have served specific functional roles in the evolution of the phenotype or because our concept of personality and the stability of behaviour needs to be revised.

Age-dependent trajectories differ between within-pair and extra-pair paternity success.

Reproductive success is associated with age in many taxa, increasing in early life followed by reproductive senescence. In socially monogamous but genetically polygamous species, this generates the interesting possibility of differential trajectories of within-pair and extra-pair siring success with age in males. We investigate these relationships simultaneously using within-individual analyses with 13 years of data from an insular house sparrow (Passer domesticus) population. As expected, we found that both within- and extra-pair paternity success increased with age, followed by a senescence-like decline. However, the age trajectories of within- and extra-pair paternity successes differed significantly, with the extra-pair paternity success increasing faster, although not significantly, in early life, and showing a delayed decline by 1.5 years on average later in life compared to within-pair paternity success. These different trajectories indicate that the two alternative mating tactics should have age-dependent pay-offs. Males may partition their reproductive effort between within- and extra-pair matings depending on their current age to reap the maximal combined benefit from both strategies. The interplay between these mating strategies and age-specific mortality may explain the variation in rates of extra-pair paternity observed within and between species.

Stabilizing survival selection on presenescent expression of a sexual ornament followed by a terminal decline.

Senescence is a decrease in functional capacity, increasing mortality rate with age. Sexual signals indicate functional capacity, because costs of ornamentation ensure signal honesty, and are therefore expected to senesce, tracking physiological deterioration and mortality. For sexual traits, mixed associations with age and positive associations with life expectancy have been reported. However, whether these associations are caused by selective disappearance and/or within-individual senescence of sexual signals, respectively, is not known. We previously reported that zebra finches with redder bills had greater life expectancy, based on a single bill colour measurement per individual. We here extend this analysis using longitudinal data and show that this finding is attributable to terminal declines in bill redness in the year before death, with no detectable change in presenescent redness. Additionally, there was a quadratic relationship between presenescent bill colouration and survival: individuals with intermediate bill redness have maximum survival prospects. This may reflect that redder individuals overinvest in colouration and/or associated physiological changes, while below-average bill redness probably reflects poorer phenotypic quality. Together, this pattern suggests that bill colouration is defended against physiological deterioration, because of mate attraction benefits, or that physiological deterioration is not a gradual process, but accelerates sharply prior to death. We discuss these possibilities in the context of the reliability theory of ageing and sexual selection.

Selective amplification and cloning of four new members of the G protein-coupled receptor family.

An approach based on the polymerase chain reaction has been devised to clone new members of the family of genes encoding guanosine triphosphate-binding protein (G protein)-coupled receptors. Degenerate primers corresponding to consensus sequences of the third and sixth transmembrane segments of available receptors were used to selectively amplify and clone members of this gene family from thyroid complementary DNA. Clones encoding three known receptors and four new putative receptors were obtained. Sequence comparisons established that the new genes belong to the G protein-coupled receptor family. Close structural similarity was observed between one of the putative receptors and the 5HT1a receptor. Two other molecules displayed common sequence characteristics, suggesting that they are members of a new subfamily of receptors with a very short nonglycosylated (extracellular) amino-terminal extension.

HLA antigen in Chinese patients with hepatocellular carcinomas.

One hundred and fourteen Chinese patients with hepatocellular carcinomas (HCC) were studied for alpha-fetoprotein (AFP), hepatitis B surface antigen (HBsAg), anti-HBsAg, and HLA markers. Younger patients with HCC (less than 60 yr old) were more significantly associated with elevated serum AFP (P less than 0.0001) and serum HBsAg (P less than 0.0001) than were older (greater than or equal to 60 yr old) patients. A strong correlation existed between serum AFP and HBsAg among the patients (P less than 0.0001). Of 27 AFP-negative patients, 15 (55.6%) had HLA-B15 compared to 53 of 238 (22.3%) healthy controls (corrected P less than 0.003, relative risk = 4.4). The frequency of HLA-B15 was even higher in the AFP-negative plus HBsAg-negative subgroup (61%). AFP-negative patients also had a significant lack of blood group A.

Immunogenetic aspects of nasopharyngeal carcinoma. IV. Increased risk in Chinese of nasopharyngeal carcinoma associated with a Chinese-related HLA profile (A2, Singapore 2).

The results of this study of 110 Singapore Chinese with nasopharyngeal carcinoma (NPC) and 91 controls confirmed the association between the occurrence of HLA antigen Singapore 2 (Sin2) and NPC in the Chinese population, and indicated that their increased risk for NPC was confined to the joint occurrence of Sin 2 and A2 antigens. These findings suggested that the genotype of importance in susceptibility to NPC is the A2-Sin 2 haplotype.

The 5'-end of bovine thyroglobulin mRNA encodes a hormonogenic peptide.

The sequence of 370 bases at the 5'-end of bovine thyroglobulin mRNA has been determined. A 41 base untranslated segment was found preceeding the ATG initiator codon. It is followed by an open reading frame providing the first data on thyroglobulin primary structure. Analysis of the amino acid sequence demonstrated the presence of an 18 residue hydrophobic segment representing a putative signal peptide. Comparison of the amino terminal sequence of thyroglobulin with that of peptides known to contain thyroid hormones [7,8] demonstrated that the first tyrosine in native thyroglobulin is mainly found as thyroxine in the mature iodinated protein [8]. Our results clearly identify the amino-terminal region of thyroglobulin as an important hormonogenic domain of the protein.

Alternative splicing may be responsible for heterogeneity of thyroglobulin structure.

During the cloning of the bovine thyroglobulin cDNA, the restriction map of one of the recombinant plasmids was in disagreement with that of the full-length double-stranded thyroglobulin cDNA. When compared to the bovine Tg mRNA sequence, this cDNA clone exhibits a 333-nucleotide deletion which corresponds precisely to 2 exons of the Tg gene. It is thus likely that alternative processing of the premessenger RNA is at the origin of the deletion. The presence of giant introns in the vicinity of the dispensable exons may also reflect some error level in the splicing mechanism. Together with previous results the alternative splicing described in this study indicates that alternative processing of the Tg transcripts may be at the origin of thyroglobulin isoforms.

Detection of alpha-fetoprotein by supplementation counterimmunoelectrophoresis (CIE).

A simple, inexpensive and sensitive method of detecting alpha-fetoprotein (AFP) by supplementation CIE assay is described. The method detects AFP at concentrations in the region of 20 ng/ml.

HLA-DQA1 allele and suballele typing using noncoding sequence polymorphisms. Application to 4AOHW cell panel typing.

HLA-DQA1 typing of the 4AOHW cell panel is presented using a novel strategy that exploits both intron and exon polymorphisms. Intron sequences adjacent to the variable HLA-DQA1 second exon exhibit stable polymorphisms that are specific for locus alleles and certain suballelic DR/DQ haplotypes. A PCR-RFLP method has been developed that is based on amplification of a 780-bp segment extending from intron 1 through exon 2 to intron 2. Stable sequence polymorphisms provide restriction enzyme sites and confer mobility variations detected on polyacrylamide minigel electrophoresis. Direct band comparison of amplified products and restriction fragments with known standards facilitates pattern comparison, obviating the requirement for accurate molecular weight determination. This method, using only two enzymes, identifies a total of 11 allelic and suballelic groups, including all eight DQA1 alleles encoded at the second exon.

Strategy for definition of DR/DQ haplotypes in the 4AOHW cell panel using noncoding sequence polymorphisms.

Our previously described intron-based DQA1-typing method provides 11 allelic and suballelic groups, including the eight alleles encoded at the second exon. Concurrent testing for the presence of the DRB3, DRB4, and DRB5 loci and the Rsa I pattern of the DRw52 group simplifies the typing requirements for allele assignment at the highly polymorphic DRB1 locus. The DRB1-allele-shortlisting process relies on known DR/DQ haplotypes. In addition to reducing the testing requirements for definitive DRB1 allele assignment, this strategy allows inference of the DR/DQ haplotype and assists in recognition of novel and/or unusual associations.

Ancient, highly polymorphic human major histocompatibility complex DQA1 intron sequences.

A 438 basepair intron 1 sequence adjacent to exon 2 in the human major histocompatibility complex DQA1 gene defined 16 allelic variants in 69 individuals from wide ethnic backgrounds. In contrast, the most variable coding region spanned by the 247 basepair exon 2 defined 11 allelic variants. Our phylogenetic human intron 1 tree derived by the Bootstrap algorithm reflects the same relative allelic relationships as the reported DQA1 exon 2 tree [Gyllensten and Erlich, Hum Immunol 36:1-10, 1989]. Thus 3' DQA1 intron 1 and exon 2 have cosegregated since divergence of the human races. Comparison of human alleles to a Rhesus monkey DQA1 first intron sequence found only 10 nucleotide substitutions unique to Rhesus, with the other 428 positions (98%) found in at least one human allele. This high degree of homology reflects the evolutionary stability of intron sequences since these two species diverged over 20 million years ago. Because more intron 1 alleles exist than exon 2 alleles, these polymorphic introns can be used to improve tissue typing for transplantation, paternity testing, and forensics and to derive more complete phylogenetic trees. These results suggest that introns represent a previously underutilized polymorphic resource.

Immunodeficiency to hepatitis B virus infection and genetic susceptibility to development of hepatocellular carcinoma.

The high frequency of hepatitis B antigen (HBsAg) in hepatocellular carcinoma (HCC) patients has led to the hypothesis that immunoresponsiveness to hepatitis B virus (HBV) may be deficient in some patients, and that the immune response deficiency may have a genetic basis. Radioelectrocomplexing (REC), a radioimmunoassay in gel based on the principle of counterimmunoelectrophoresis (CIE), has been used to identify four HBV immune status subgroups: 1) HBsAg +ve/HBsAb +ve; 2) HBsAg +ve/HBsAb -ve; 3) HBsAb -ve/HBsAb +ve; 4) HBsAg -ve/HBsAb -ve/HBsAb -ve. These subgroups comprise 2, 6, 70, and 22 percent, respectively, among blood donors, and 32, 19, 23, and 26 percent, respectively, among HCC patients. Although the HBV exposure rates in the two groups were similar, the immune complexemic rates and HBs antigenemic rates were significantly higher in HBB patients than in the blood donors. It is proposed that the failure of termination of HBV infection revealed by these high rates reflects an immunodeficiency state characterized by an inability to produce high-avidity HBsAb. The immunodeficiency might have a primary genetic basis, or it might be secondary to the immunodepressive effects of concurrent viral or parasitic infections.

Transfusion of hepatitis B immune complex-containing blood in high HBV prevalence populations.

In several countries where there is a high prevalence of HBV the risk of PTH has been investigated. One study demonstrated that HBV immunity provided protection against infection following transfusion of HBs Ag-postive blood in that a higher proportion of immune recipients failed to develop, or developed only transitory, HBs antigenemia, Forty (61 per cent) of 66 recipients who received HBs Ag positive (IAHA) units developed hepatitis, which was subclinical in 37 (93 per cent) of the 40. Six recipients of HBs Ag-containing units had HBs Ag in the pre-transfusion serum. In four, HBs Ag disappeared in the early post-trasfusion period, and anti-HBs was detected within days, persisting for the duration of the study. The mechanism of this change in HBV immune status is unknown but it may be related to the existence of HBs Ag immune complexemia detectable by radioelectro-complexing in approximately 80 per cent of Hbs Ag-positive blood donors. The phenomenon of apparent "cure" of the HBs antigenemic state warrants further attention.