The color and structure of the human iris. 1. Morphological studies]

The material basis of this investigation consists of empirical findings and colour photographs of the irises of 200 pairs of twins and 100 control pairs. For the morphological investigation first-born twins and control persons are combined to constitute a comparative group of 400 non-related testees. Research by means of the iris microscope and the evaluation of standardized iris photographs led to the development of a catalogue of features which describes 10 iris characteristics for the iris colour and 20 for the iris structure. For each feature different degrees of markedness are defined and their frequency is determined. Similarly, intraindividual right/left and sex differences as well as age-dependencies and the relation between the features are examined. The setting-up of features includes outlining an iris-colour class system in order to render a better and more practicable determination of eye colour possible. As a substitute for Martin/Schulz's table of eye-colour, which describes only eye-colour phenomena, 4 iris-colour classes are set up whose main criterion of classification is the quantity of pigment. When we consider the testees of all age classes, sex differences have no statistical relevance as for iris colour. Only in the case of male testees may an intensive decrease of blue and brown iris colour in favour of combination colours (yellow pigment colours in particular) be observed during the phase of puberty. Therefore, the brightening postulated in the relevant literature can be confirmed. With regard to female testees, in contrast, pigment shifting is of no statistical relevance. After a slight brightening the irises numerically re-darken at the adult-stage to the initial child level, i.e. they become "dark again" rather than just become "darker". Within the iris structure only the characteristics of the anterior stroma leaf show sex differences. They are, however, only weakly marked and can be described merely as a trend. Over the whole range of the age classes, there are no outstanding structural differences. The different iris characteristics concerning iris colour stand in a significant relation to each other. When we consider the statistically relevant relations between structural features, it becomes clear that particularly reduced and particularly intact iris characteristics correlate. Thus, we can distinguish between an intact type of iris and a reduced one. Three quarters of the testees, however, combine reduced and intact properties with medium degrees of markedness.(ABSTRACT TRUNCATED AT 400 WORDS)     

The color and structure of the human iris. 2. Studies of 200 twins]

Subject of the present report is an investigation of the heredity of 30 iris characteristics. The material basis of this sample of twins (100 monozygotic and 100 dizygotic pairs), the largest ever taken as a basis for the purpose of iris research, consists of standardized colour photographs of the examined persons' irises and iris-microscopic observations. The pairs of twins are compared to 100 non-related casual pairs in order to render a better estimation of the degree of heredity of the features possible. On every occasion several classes were constituted for the concordance verification. These classes result from the number of the classes of the forms of markedness and present different levels of similarity. The different distribution of the twin pairs and the control pairs on the concordance classes are always examined for their statistical significance, and for each group of pairs a concordance value is computed. The intervals between the concordance values of the monozygotic and dizygotic pairs and the control pairs indicate the degree of heredity of the investigated feature. Taking all the compiled factors and conditions into consideration, an evaluation of the features as heredity features is made. Though a hereditary component can be observed for all iris characteristics, only about a third could be called heredity features. Quantity of pigment and the hitherto undescribed limiting layer folds were evaluated as "very good", whereas pigment colour in the fine analysis, quality of the anterior stroma leaf, frequency of iris crypts and iris frill position were judged as "good". Tone of blue, markedness of Woelfflin nodules, quantity and markedness of contractional rings could be evaluated as "moderately good" as to their heredity. On the basis of the prior concordance investigations for each of the 300 pairs, a "similarity index" and a "concordance index" were computed in order to arrive at evidence as to the degree of similarity of the single pairs; i.e. in order to detect the limits of the similarity between non-identical twins and the dissimilarity between identical twins. This concluding investigations lead to the question of the possibility of a diagnosis of genetic identicalness solely on the basis of the comparison of irises.     

New explanation for elements of Hainan Island's biological assemblage may stretch things a little too far

Recent interpretations of various floral and faunal components on Hainan Island and the nearby parts of mainland east Asia invoke a mid‐Cenozoic plate‐tectonic rifting episode that displaced the landmass ca 220 km south‐eastwards from a postulated former site directly adjacent to the China– Vietnam border. However, having sifted through the relevant geological evidence I contend that this idea is weakly founded. In explaining challenging biogeographical patterns, it is suggested that all of the geo‐physical processes that could have forged the distributions need to be considered.     

Gray plumage color is more cryptic than brown in snowy landscapes in a resident color polymorphic bird

Camouflage may promote fitness of given phenotypes in different environments. The tawny owl (Strix aluco) is a color polymorphic species with a gray and brown morph resident in the Western Palearctic. A strong selection pressure against the brown morph during snowy and cold winters has been documented earlier, but the selection mechanisms remain unresolved. Here, we hypothesize that selection favors the gray morph because it is better camouflaged against predators and mobbers in snowy conditions compared to the brown one. We conducted an online citizen science experiment where volunteers were asked to locate a gray or a brown tawny owl specimen from pictures taken in snowy and snowless landscapes. Our results show that the gray morph in snowy landscapes is the hardest to detect whereas the brown morph in snowy landscapes is the easiest to detect. With an avian vision model, we show that, similar to human perceivers, the brown morph is more conspicuous than the gray against coniferous tree trunks for a mobbing passerine. We suggest that with better camouflage, the gray morph may avoid mobbers and predators more efficiently than the brown morph and thus survive better in snowy environments. As winters are getting milder and shorter in the species range, the selection periods against brown coloration may eventually disappear or shift poleward.     

Muscanone: a 3-O-(1", 8", 14"-trimethylhexadecanyl)naringenin from Commiphora wightii

A new antifungal flavanone, muscanone (1), was isolated along with known naringenin (2) from Commiphora wightii (Arn.) Bhandari (Burseraceae) by directing the fractionation of an EtOH extract of the air-dried trunk of C. wightii with microbial sensitivity assay. The structures of 1 and 2 were determined from EIMS, HREIMS, DEPT, 1H-1H COSY, HSQC and HMBC spectral data. Muscanone (1) was identified as 3-O-(1", 8",14"-trimethylhexadecanyl)naringenin and was found to be active against Candida albicans. The isolation, structure elucidation, NMR spectral assignments, and bioactivities of 1 and 2 are reported.     

Three genome-wide association studies and a linkage analysis identify HERC2 as a human iris color gene

Human iris color was one of the first traits for which Mendelian segregation was established. To date, the genetics of iris color is still not fully understood and is of interest, particularly in view of forensic applications. In three independent genome-wide association (GWA) studies of a total of 1406 persons and a genome-wide linkage study of 1292 relatives, all from the Netherlands, we found that the 15q13.1 region is the predominant region involved in human iris color. There were no other regions showing consistent genome-wide evidence for association and linkage to iris color. Single nucleotide polymorphisms (SNPs) in the HERC2 gene and, to a lesser extent, in the neighboring OCA2 gene were independently associated to iris color variation. OCA2 has been implicated in iris color previously. A replication study within two populations confirmed that the HERC2 gene is a new and significant determinant of human iris color variation, in addition to OCA2. Furthermore, HERC2 rs916977 showed a clinal allele distribution across 23 European populations, which was significantly correlated to iris color variation. We suggest that genetic variants regulating expression of the OCA2 gene exist in the HERC2 gene or, alternatively, within the 11.7 kb of sequence between OCA2 and HERC2, and that most iris color variation in Europeans is explained by those two genes. Testing markers in the HERC2-OCA2 region may be useful in forensic applications to predict eye color phenotypes of unknown persons of European genetic origin.     

"Glutaraldehyde-P", a stable, reactive aldehyde matrix for affinity chromatography

A high-performance affinity chromatography support based on silica has been developed for the immobilization of proteins containing primary amino groups. A hydrophilic polymer covalently bound to the silica surface minimizes nonspecific protein binding to the support while preserving high binding capacity. The Schiff base reaction involved in the coupling of a ligand to the affinity medium is rapid, allows the use of mild conditions during the coupling process, and results in a very stable linkage. Reaction parameters were studied for protein coupling to the affinity support to determine optimum binding conditions and dynamic capacity as a function of protein size. The stability of the ligand-matrix bond was determined. The performance and reproducibility of the affinity support are demonstrated by its use in the analysis of nitrophenyl sugar derivatives, purification of glycoproteins, and isolation of anti-bovine immunoglobulin G developed in rabbit.     

Action of "myelauxins", substances capable of accelerating granulocytic hematopoiesis, in vivo in rabbits]

Extracts from homologous blood serum had been shown by the author to stimulate the granulocytopoiesis of cells from chickens' embryonic spleen cultivated in vitro. The results presented here show that extracts obtained with the same method from rabbits' serum can induce the same activity in vivo in the adult mammals. Data relating to the nature of those active substances will be published later.     

The "prostaglandin step", a bottleneck in the activation of the uterus

Uterine strips were excised from post partum rabbits, mounted $\text{in vitro}$ and stimulated electrically to sustain cyclic tension at a maximal value. Within 10–15 minutes after exposure to 1.5–2.0 mg/ml Naproxen (a derivative of propionic acid and an inhibitor of PG-synthesis) uterine tension decreased to less than 25% of the original value. The effect of Naproxen (N), also observed in spontaneously active (unstimulated) uteri, was suspended by removing N through washing the strips with mammalian Krebs' solution.When suppressed by N, uterine tension could be restored by exogenous PG F2α but not by oxytocin, in spite of a 1000 fold increase in that oxytocin concentration which effectively stimulated the normal uterus (unexposed to N). This failure of oxytocin in promoting activation, when the PG-synthesis of the uterus was blocked, suggest that endogenous PGs participate in a critical step of the sequence of events which provoke myometrial activity.     

Genome features of "Dark-fly", a Drosophila line reared long-term in a dark environment

Organisms are remarkably adapted to diverse environments by specialized metabolisms, morphology, or behaviors. To address the molecular mechanisms underlying environmental adaptation, we have utilized a Drosophila melanogaster line, termed "Dark-fly", which has been maintained in constant dark conditions for 57 years (1400 generations). We found that Dark-fly exhibited higher fecundity in dark than in light conditions, indicating that Dark-fly possesses some traits advantageous in darkness. Using next-generation sequencing technology, we determined the whole genome sequence of Dark-fly and identified approximately 220,000 single nucleotide polymorphisms (SNPs) and 4,700 insertions or deletions (InDels) in the Dark-fly genome compared to the genome of the Oregon-R-S strain, a control strain. 1.8% of SNPs were classified as non-synonymous SNPs (nsSNPs: i.e., they alter the amino acid sequence of gene products). Among them, we detected 28 nonsense mutations (i.e., they produce a stop codon in the protein sequence) in the Dark-fly genome. These included genes encoding an olfactory receptor and a light receptor. We also searched runs of homozygosity (ROH) regions as putative regions selected during the population history, and found 21 ROH regions in the Dark-fly genome. We identified 241 genes carrying nsSNPs or InDels in the ROH regions. These include a cluster of alpha-esterase genes that are involved in detoxification processes. Furthermore, analysis of structural variants in the Dark-fly genome showed the deletion of a gene related to fatty acid metabolism. Our results revealed unique features of the Dark-fly genome and provided a list of potential candidate genes involved in environmental adaptation.     

Suppression of "fast" IPSP,superposed on "slow", as a possible cause of priming in murine hippocampus

Intra- and extracellular response in area CA1 to stimulation of two independent afferent inputs, one a priming or conditioned and the other a test or primed input (C1 and C2, respectively) were recorded in surviving murine hippocampal slices. Duration and amplitude of test field potentials (FP) and of excitatory postsynaptic potentials (EPSP), were measured, as well as amplitude of "fast" and "slow" components of inhibitory postsynaptic potentials or stimulation varying between 0 and 1 sec. Conditioning brought about an increase in the duration of FP, in duration and amplitude of EPSP, and suppression of IPSP at intervals of between 50 and 500 msec peaking at 200 msec (i.e., priming effect). These changes correlated with level of IPSP_b in response to conditioned stimuli. The most pronounced effect could be seen in neurons manifesting hyperpolarizing IPSP in response to test stimuli. Suppression of test IPSP_a after superposition on IPSP_b is thought to bring about the increase in test FP and EPSP seen during priming.Institute for Brain Research, All-Union Mental Health Research Center, Academy of Medical Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 22, No. 6, pp. 730–739, November–December, 1990.