Western Caucasians Research Articles

Putting Culture Under the ‘Spotlight’ Reveals Universal Information Use for Face Recognition

BackgroundEye movement strategies employed by humans to identify conspecifics are not universal. Westerners predominantly fixate the eyes during face recognition, whereas Easterners more the nose region, yet recognition accuracy is comparable. However, natural fixations do not unequivocally represent information extraction. So the question of whether humans universally use identical facial information to recognize faces remains unresolved.Methodology/Principal FindingsWe monitored eye movements during face recognition of Western Caucasian (WC) and East Asian (EA) observers with a novel technique in face recognition that parametrically restricts information outside central vision. We used ‘Spotlights’ with Gaussian apertures of 2°, 5° or 8° dynamically centered on observers' fixations. Strikingly, in constrained Spotlight conditions (2° and 5°) observers of both cultures actively fixated the same facial information: the eyes and mouth. When information from both eyes and mouth was simultaneously available when fixating the nose (8°), as expected EA observers shifted their fixations towards this region.Conclusions/SignificanceSocial experience and cultural factors shape the strategies used to extract information from faces, but these results suggest that external forces do not modulate information use. Human beings rely on identical facial information to recognize conspecifics, a universal law that might be dictated by the evolutionary constraints of nature and not nurture.

Inverting Faces Does Not Abolish Cultural Diversity in Eye Movements

Face processing is widely understood to be a basic, universal visual function effortlessly achieved by people from all cultures and races. The remarkable recognition performance for faces is markedly and specifically affected by picture-plane inversion: the so-called face-inversion effect (FIE), a finding often used as evidence for face-specific mechanisms. However, it has recently been shown that culture shapes the way people deploy eye movements to extract information from faces. Interestingly, the comparable lack of experience with inverted faces across cultures offers a unique opportunity to establish the extent to which such cultural perceptual biases in eye movements are robust, but also to assess whether face-specific mechanisms are universally tuned. Here we monitored the eye movements of Western Caucasian (WC) and East Asian (EA) observers while they learned and recognised WC and EA inverted faces. Both groups of observers showed a comparable impairment in recognising inverted faces of both races. WC observers deployed a scattered inverted triangular scanpath with a bias towards the mouth, whereas EA observers uniformly extended the focus of their fixations from the centre towards the eyes. Overall, our data show that cultural perceptual differences in eye movements persist during the FIE, questioning the universality of face-processing mechanisms.

Intergeneration CAG expansion and contraction in a Chinese HD family

The prevalence of juvenile-onset Huntington's disease (HD) is about ten times lower than adult HD. Here we report a Chinese HD family showing both intergeneration CAG expansion and contraction. The expansion resulted from a paternal transmission which leads to juvenile-onset HD for a 17-year-old Chinese boy (III-5). More interestingly, a contraction was noticed in a maternal transmission (III-3), which changed the CAG repeat from an expanded, disease-causing allele (48 repeats) to a normal or intermediate allele (34 repeats). Of note, the contraction resulted in a deletion of 14 CAG repeats, which is much larger than previously reported contractions. Our results are consistent with previous observations in Western Caucasians that juvenile-onset HD is more likely inherited through the male germline.

Weight and dimensions of the pituitary in northwestern Indians

Weight and dimensions of the pituitary (hypophysis cerebri) obtained from medicolegal autopsies of northwestern Indian subjects, which included 87 children and adolescents and 798 adults were recorded. Volume of the pituitary was determined in 100 specimens. In addition, anteroposterior and vertical measurement of pituitary were taken in mid-sagittal sections of the head in magnetic resonance images (MRI) of 130 living adults. In the males, the weight of pituitary increased steadily from 102.52 +/- 38.66 mg in the age group of 0-5 years to 427.83 +/- 117.15 mg in the age group of 36-45 years, it decreased thereafter. In the females, the weight increased from 166.10 +/- 38.70 mg in the first age group to 445.90 +/- 168.60 mg in the age group of 16-17 years and became erratic thereafter. The mean weight of the gland in female subjects was always more than in the males of the corresponding ages till 35 years (p < 0.001, p < 0.01, p < 0.05). The maximum weight of the pituitary was observed during adolescence in the females. When weights of the gland of all the age groups were pooled together in adults the average weight was 401.26 +/- 105.89 mg in the males and 417.32 +/- 104.07 mg in the females. The weight and dimensions of the gland in northwestern Indian subjects were smaller than those in the western Caucasians and Japanese. In mid-sagittal MRI pictures of the head, the anteroposterior and vertical measurement of pituitary were about one mm greater than in the autopsy specimens. In the males, weight of the gland was significantly related to body weight in children, adolescents and adults; it was related to supine body length only in the adults. In the females, weight of the gland was significantly correlated with age in all the age group except in the age group of 36-55 years.

FMR1 haplotype analyses among Indians: a weak founder effect and other findings.

This study on allelic/haplotypic fragile X associations evaluated using STR (DXS548, FRAXAC1, FRAXAC2) and SNP (ATL1) markers flanking the (CGG)(n) locus of FMR1is the first report from the large ethnically complex Indian population. Results have been compared with allele/haplotype distributions reported for other major ethnic groups, including White Caucasians, Africans, and Pacific Asians. Though overall allele frequency distributions at the individual loci are more similar to Western Caucasians compared with others, significant differences are observed in haplotypic associations with the mutated X. The striking findings are: (1) high diversity and heterozygosity of haplotypes among fragile X chromosomes ( n=40) and controls ( n=262), including four haplotypes found exclusively in this study sample; (2) weak association of DXS548-FRAXAC1-FRAXAC2 haplotypes, 2-1-3, 6-3-3+ and 7-4-6+ with the disorder, and absence of White Caucasian fragile X haplotypes 6-4-4 and 6-4-5; (3) weak founder effect for the fragile X expansion mutation in the Indians; (4) lack of a continuum of haplotype-based FMR1 alleles between intermediate (CGG)(n) size ranges and expanded alleles; (5) exclusion of ATL1 as a candidate genetic indicator of FMR1 instability. The high STR-based haplotype diversity observed among fragile X lineages, irrespective of ethnic alliances, strongly suggests the inappropriateness of using STR haplotypes to infer predisposition to instability among ethnically separated fragile X pedigrees and may reiterate the need for identifying newer SNPs from this region to not only determine true founder effects for the fragile X mutation, but also decipher possible mechanisms leading to CGG instability.

Smoking, low density lipoprotein cholesterol, fibrinogen and myocardial infarction before 41 years of age: a Danish case-control study.

Of major coronary risk factors, smoking and total cholesterol were significant in a previous Danish case-control study of myocardial infarction at a young age. To determine whether smoking was an important coronary risk factor in the context of new and major anthropometric and biochemical risk factors for myocardial infarction in individuals less than 41 years of age. A prevalence hospital-based matched case-control study of young individuals. We selected 22 Caucasian cases and 24 Caucasian controls without coronary heart disease matching for age and gender and studied a series of major coronary risk factors and newer anthropometric and biochemical variables. In conditional univariate logistic regression analyses, the following factors were significantly associated with the coronary risk: family history, social class, smoking, intraabdominal adipose tissue area as percentage of total abdominal adipose tissue area on a CT scan, glycosylated haemoglobin level, systolic blood pressure, total cholesterol, low density lipoprotein (LDL) cholesterol, homocysteine, and fibrinogen levels (P < 0.05). However, in multiple conditional logistic regression analyses, only smoking, LDL cholesterol, and fibrinogen levels remained significant. Ten cases (46%) and none of the 24 controls were smokers with a LDL cholesterol level 4.5 mmol/l and a fibrinogen level 3.7 g/l (P = 0.0003, Fisher's exact test). Out of a series of major and newer coronary risk factors in young Western Caucasians, smoking, and levels of LDL cholesterol, and fibrinogen were independent significant coronary risk factors. The findings need to be validated in prospective studies.

Anorexia Nervosa: A caucasian syndrome rare in Asia

Anorexia Nervosa (AN) is an eating disorder characterised by deliberate weight loss that is induced and sustained by the patient. The disorder usually occurs in females. The patient has body image distortion and experiences herself as fat despite being grossly underweight. AN is virtually restricted to Western Caucasians. There were no cases detected in a recent Indian study group at risk, though some atypical case were reported earlier [1]. The occurrence of a typical case satisfying all the diagnostic criteria in an Indian girl is rare, and may be the fall out of Western acculturation of our population.

The HLA genes and their diverse polymorphism

Advanced DNA level studies based on HLA class II sequence analysis have revealed considerable diversity in HLA among Asian Indians. High resolution typing of specific alleles such as DR2 and DR4 in the HLA class II region by PCR-SSP or SSOP hybridization and their associated DR-DQ haplotypes have helped to detect unique haplotypes and novel alleles which have subsequently been confirmed by sequencing. Incidentally, remarkable stability has been maintained in several other DRB1 alleles viz. DR1, DR7, DR9 and DR10. The ARMS-PCR technology has been found to be particularly useful for typing HLA-A, HLA-B and HLA-Cw alleles. These technologies are far superior over serological methods. Our studies have shown remarkable heterogeneity of common HLA-A and B alleles in Asian Indians. Molecular subtyping of HLA-A2 revealed that subtype A(*)0211 is found only in Indian population and may be the result of selection pressure in this population. Investigations into polymorphism in the HLA-B27 gene revealed that subtypes common both to the western caucasians and orientals occur in the Indian population. It is apparent that the population of the Indian subcontinent, placed as it is between the Caucasoids and Negroids on one hand and Australoids and Mongoloids on the other, provides a rich source of many HLA haplotypes. While the most frequent Caucasian haplotypes occur with a reasonable frequency in Asian Indians, those found predominantly in other ethnic groups (e.g., australian Aborigines and populations of Oceania, China and Japan) are also detected. Knowledge on this is most important for donor selection during organ and bone marrow transplantation and for designing MHC targeted vaccines in specific diseases.

Population screening for hemochromatosis: has the time finally come?

Hemochromatosis refers to a group of common heritable disorders among Western Caucasians which increase susceptibility for development of iron overload and its complications. These consequences are preventable by early detection and simple, relatively inexpensive treatment. Screening of appropriate populations to detect hemochromatosis before iron overload occurs is both effective and cost-effective. The primary goal of screening should be the ongoing detection of persons with hemochromatosis, especially healthy individuals whose risk to develop iron overload is great, in a context that provides appropriate preventive treatment, education, and counseling. Although related issues warrant further study, implementation of well-designed screening programs for hemochromatosis should not be delayed.

Asian Indian HLA-DR2-, DR4-, and DR52-related DR-DQ genotypes analyzed by polymerase chain reaction based nonradioactive oligonucleotide typing unique haplotypes and a novel DR4 subtype

We have employed a PCR-based nonradioactive technique using biotinylated SSOPs to define HLA-DR2-, 4-, DR51-, and DR52-associated DR-DQ genotypes in Asian Indian families. In the DR2 group, most haplotypes described by us in a previous study were confirmed by family analysis. Evidence for one additional haplotype was available in this study. The classic DRB1*1501- and DRB1*1502-associated caucasoid haplotypes occurred with an appreciable frequency in Asian Indians, but two of the DRB1*1601-associated Caucasoid haplotypes were absent. At least six unique and unusual DR2-associated genotypes were encountered. In the DR52 group, the three most common alleles are DRB1*0301, DRB1*1404, and DRB1*1101. The DR6-associated alleles were DRB1*1301, 1302, 1401, and 1404. A few unique haplotypes occurred with low frequency in this group. In the DR4 group, at least three unusual patterns of hybridization were noticed by family analysis. One of these appears to be a novel DR4 subtype upon sequencing. These results demonstrate that, besides HLA-DR2, appreciable complexity occurs in the DR4- and DR52-associated alleles among Asian Indians. The presence of unique DR-DQ haplotypes in addition to those found characteristically among Western Caucasians suggests that the Indian population provides valuable source of many HLA class II haplotypes.

Analysis of HLA-DR2-associated polymorphisms by oligonucleotide hybridization in an Asian Indian population

Among major histocompatibility complex class II antigens, HLA-DR2 appears to have a much larger degree of polymorphism than usually recognized by routine serology or restriction fragment length polymorphisms. We have utilized oligonucleotide probes to further identify the DR2 specificity and its molecular subtypes on the basis of specific DNA sequences as they occur in a select sample from the Asian Indian population. In addition, oglinucleotide typing of HLA-DQA1 and -DQB1 genes allowed us to determine specific associations of DRB1, DRB5, DQA1, and DQB1 alleles in DR2 individuals. A set of 60 oligonucleotide probes were hybridized to polymerase chain reaction (PCR)-amplified DNA from DR2 homozygous or heterozygous individuals. The most common DR2 subtypes that occured in this selected population are: DRB1 ∗1501 (60%), DRB1 ∗1502 (33.8%), and DRB1 ∗1602 (6.2%). No example of DRB1 ∗1601 was detected. By combining these results with the allelic variations at DQA1 and DQB1, we were able to detect at least seven different haplotypes, the most common being DRB1 ∗1502-DRB5 ∗0102- DQA1 ∗0103-DQBI ∗0601 and DRBI ∗1501-DRB5 ∗0101 DQA1 ∗0102-DQB1 ∗0502. At least five unexpected combinations, not reported among Western Caucasians, were noticed in this sample. Thus oligonucleotide typing is a valuable tool for defining further polymorphisms in the HLA-D region as exemplified by its applications to typing DR2-positive patients with tubercoloid leprosy and pulmonary tubercolosis.