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PubMed1977

Adaptation at specific loci. I. Natural selection on phosphoglucose isomerase of Colias butterflies: Biochemical and population aspects.

Electrophoretic variants of phosphoglucose isomerase (PGI) in Colias butterflies have been studied from field and laboratory viewpoints. The transmission pattern is that of a dimeric enzyme controlled by one structural gene locus. Populations usually harbor four to six allelic mobility classes. These mobility classes are shared among species complexes, though their frequencies differ widely. Preliminary Ferguson plot analysis of the variants has been carried out. Purified preparations of Colias PGI alleles are more effective in standardizing Ferguson plots than heterologous proteins, such as ferritin. Variation of Ferguson plot parameters is not an infallible guide to electrophoretically "cryptic alleles," as one putative case proved to be due to nonallele-specific effects. S, M, and F mobility classes in two Colias semispecies show the same retardation coefficients in Ferguson plots. Adults early in the flight periods of their nonoverlapping generations show genotype frequencies in Hardy-Weinberg equilibrium, but heterozygote excess develops as the insects age. Simple directional selection and large-scale population mixing are unlikely to be causes of this, although several other selection modes remain possible. Identical-by-descent lines of the four frequent-to-common alleles in C. eurytheme have been set up in culture, and enzyme has been purified from these for study of functional properties. Major differenecs in heat stability and in various kinetic parameters are found among the ten possible genotypes. In some cases, heterosis for kinetic parameters is seen; in other cases, opposing trends in kinetic function and heat stability create potential for net heterosis in function. Possible interpretations of these results in an adaptive metabolic context are discussed, and directions for further work are stated.

Animals↗
PubMed1976

Irregular antibodies causing hemolytic disease of the newborn.

The known antigens associated with hemolytic disease of the newborn along with the degree of severity of the disease caused by each antigen are presented in Table 13. The genotype frequencies for the major blood groups have been presented in the text. It is hoped that this information will help the clinician in managing sensitization to irregular antibodies and in predicting the likelihood of future affected siblings. Proper periodic screening of the antenatal patient for irregular antibodies can alert the physician to a potential problem with hemolytic disease and alert the laboratory so that time is available to find acceptable donors. One should always remember that autologous blood transfusion can be used if time is available to obtain the blood. When the antenatal patient with an irregular antibody presents, the husband should be tested for the presence of the antigen. If present, the physician should determine the severity of the disease that can be caused by this antibody and manage the patient appropriately. It is hoped that with good antenatal care, the morbidity and mortality of hemolytic disease of the newborn can be diminished.

Blood Group Antigens↗
PubMed1979

Close association between particular I region-determined cell surface antigens and Ir gene-controlled immune responsiveness to synthetic polypeptides in wild rats.

The relationship between major histocompatibility complex (MHC) and genetic control of immune responsiveness to the synthetic polypeptides (T,G)-A--L [poly-(LTyr,LGlu)-poly(DLAla)--poly(LLys)] and (H,G)-A--L [poly(LHis,L-Glu)-poly-(DLAla)--poly(LLys)] has been studied in 26 wild rats. The major histocompatibility complex (MHC) genotype frequencies observed were not different from those expected according to the Hardy-Weinberg formula. More than half of the wild rats carried MHC-linked responder Ir-TGAL and Ir-HGAL genes. High or intermediate responsiveness to (T,G)-A--L and high responsiveness to (H,G)-A--L were always found to be associated with particular I region-determined cell surface antigens. These antigens could be identified serologically and by primary and secondary mixed lymphocyte reactions, and were similar or identical to I region products of (T,G)-A--L high responder or (H,G)-A--L intermediate responder inbred rat strains. The strong association between cell surface antigens and immune responsiveness could be due to linkage disequilibrium or to pleiotropy. Since the same I region-determined cell surface structure could be associated either with high or intermediate anti-(T,G)-A--L antibody titers, the presence of the Ia antigen(s) identified did not seem to guarantee high antibody responsiveness to the test antigen.

Animals↗
PubMed1976

Polymorphism in a cyclic parthenogenetic species: Simocephalus serrulatus.

A survey of sixteen isozyme loci using electrophoretic techniques was conducted for three isolated natural populations and one laboratory population of the cyclic parthenogenetic species, Simocephalus serrulatus. The proportion of polymorphic loci (33%-60%) and the average number of heterozygous loci per individual (6%-23%) in the three natural populations were found to be comparable to those found in most sexually reproducing organisms. Detailed analyses were made for one of these populations using five polymorphic loci. The results indicated that (1) seasonal changes in genotypic frequencies took place, (2) apomicitic parthenogenesis does not lead to genetic homogeneity, and (3) marked gametic disequilibrium at these five loci was present in the population, indicating that selection acted on coadapted groups of genes.

Alkaline Phosphatase↗
PubMed1979

Genetic tags applied to the European hake, Merluccius merluccius (L.).

Three biochemical gene markers test the hypothesis that the European hake, Merluccius merluccius (L.), along the west European continental shelf are one race. The three polymorphic loci were serum transferrin (Tf), eye vitreous fluid butyric esterase (Es) and liver superoxide dismutase (Sod). Five transferrin alleles, three esterase alleles and two superoxide dismutase alleles were identified. Heterogeneity tests on genotype frequency distribution for twelve areas ranging from Norway to Biscay revealed no significant variation. The results using these genetic tags are consistent with the unit race hypothesis for hake throughout the sea areas sampled.

Alleles↗
PubMed1977

Polymorphisms of the haptoglobin peptide chains in Pyrenean populations.

This study has analyzed the haptoglobin genotype frequencies in over 900 samples from populations living on the Northern slopes of the Pyrenees. The results emphasize the importance of systematically determining the frequencies of the Hp1S, Hp1F, Hp2SS, Hp2FF, Hp2FS alleles. Hp1S was the predominant allele, the HpIS/Hp1 distribution varying between .5 and .69 as in most European populations. Hp2 alleles were observed in low frequency with differences in geographically distinct samples. Pyrenean populations in the western zones (Basques and Baronnies) were found to contain the Hp2FF allele while those in eastern regions, the Hp2SS allele. We have speculated that Hp2SS is as old as the Hp2FF, arising from southern Mediterranean areas, and suggest that Pyrenean groups have different origins.

Alleles↗
PubMedDate not supplied

[Modifying effect of the female genotype on the frequency of t-haplotype transmission to the progeny of T/t6 compound male mice].

Female genotype effects on the transmission of t-haplotypes from heterozygous males to offspring has been established. The CBA females transmitted T-gene to 29 per cent, C57BL/6 females to 47 per cent, and F1 hybrid females to 39 per cent of their offspring. The differences in the transmission rate are supposed to depend on female genotype and to be determined by selective ageing of T-carrying sperms in female genital tract when compared to t6-carrying sperms, because the interval between copulation and syngamy in C57BL/6 females is shorter than in CBA females. These data indicate the phenotypical differences between T- and t6-carrying sperms.

Alleles↗
PubMed1975

A continuous selective model for an X-linked locus.

Neglecting age-structure, but taking into account matings with differential fertility in Mendelian reproduction, a continuous selective model is formulated for a single X-linked locus with an arbitrary number of alleles. Without restricting the mating system, differential equations are derived for the genotypic and allelic frequencies. Assuming random mating, no selection, and constant fertilities and mortalities, these differential equations are solved explicitly. For this case, in contrast to the corresponding phenomenon in the usual model with discrete, non-overlapping generation, the difference between the frequencies of any allele in males and females approaches zero without oscillation.

Age Factors↗
PubMed1978

HLA antigens in two Iranian populations: the Armenians and the Jews.

The distribution of HLA phenotype, genotype and haplotype frequencies was studied in two Iranian populations, the Armenians and the Jews. Although the frequencies of most antigens in the Armenians have approximately the average Jewish values, haplotype frequencies are quite different between the two populations. The frequencies of antigens in Iranian Jews are more similar to those in the Mazandaranies, a group of non-Jewish Iranians, than to the Jewish populations from Yemen and Cochin, India.

Armenia↗
PubMedDate not supplied

Estimation of genotypic and environmental variation in plants.

The frequency of genotypes with the desired degree of expression of economically important quantitative characters within a hybrid or mutant population is usually very low. Therefore, the early identification and selection of such genotypes involves the analysis of very large populations. Because the breeding values of individuals in a population are masked by environmental, competitional, and ontogenic noises, special quantitative--genetic methods of analysis have to be used in order to eliminate their disturbing effects. The present chapter deals with a new approach to such an analysis by using either a simple background character or a background index obtained as a linear function of two, or more than two, background characters. It is believed that the use of this approach would greatly increase the efficiency of selection and shorten the time needed to produce improved new crop cultivars. As the analyses require the handling of large amounts of measurement data, plant breeders must use computer facilities.

Environment↗
PubMed1976

Expectations for inbreeding depression on self-fertilization of tetraploids.

The contribution to the inbreeding depression from a digenic tetrasomic locus upon self-fertilization involves three genotypic interaction effects which may be thought of as a generalization of the dominance deviation for a diploid locus. It is shown how this contribution may be expressed in terms of these genotypic interaction effects, the gene frequencies and the number of generations of selfing.

Alleles↗
PubMed2025

Frequency and Distribution of KIR Genotypes of Donors-Recipient Pairs in the Haploidentical Haematopoietic Stem Cell Transplantation Setting: Collaborative Study by the Spanish Working Group in Histocompatibility and Transplant Immunology (GETHIT) and the Spanish Haematopoietic Transplantation and Cell Therapy Group (GETH-TC).

There is limited information regarding the influence of KIR genotype, compared to the HLA system, in haploidentical haematopoietic stem cell transplantation (haplo-HSCT). This study aimed to determine the frequencies of KIR genotypes in Spanish haematologic patients undergoing haplo-HSCT. A study was conducted on 113 oncohaematological patients and their donors, treated across five centres that are members of the Spanish Working Group in Histocompatibility and Transplant Immunology (GETHIT) and the Spanish Haematopoietic Transplantation and Cell Therapy Group (GETH-TC). KIR typing was performed using PCR-rSSO or PCR-SSP. KIR genotypes were identified using the KIR Allele Frequency Net Database. Among donors, the most frequent KIR genotypes were Type 1 (28.3%), Type 2 (12.4%) and Type 4 (10.6%). In patients, Genotypes 1 (23.9%), 4 (23%) and 2 (14.2%) were most prevalent. Donors exhibited AA centromeric (46%) and telomeric (59.3%) types, while patients had a higher AB centromeric frequency (52.2%). Differences were observed in the BB centromeric type (3.5% patients; 16.8% donors, p = 0.002). The AB KIR genotype was the most common (70.8% donors; 75.2% patients). Most were classified as 'neutral' (61.9% donors; 73.5% patients). B-content score1 was the most common (48.7% patients; 33.6% donors). Notably, classification as best was rare (2.7% patients; 16.8% donors, p = 0.002). The study highlights the distribution of KIR genotypes in haplo-HSCT patients and donors, with Genotypes 1, 2 and 4 being the most prevalent. AB KIR genotypes and B-content score 1 were dominant. Moreover, KIR genotypes ID may serve as criteria for future investigation about the immunogenetic predisposition to malignant haematological diseases.

Humans↗
PubMed1976

[The role of variable selective factors in the maintainence of polymorphism in Drosophila melanogaster: models and comparison to experimental populations].

During the study of Drosophila melanogaster experimental populations, the adaptiive values of three genotypes corresponding to sepia locus were measured, and a frequency dependent selection model was proposed. This model and the overdominance model are compared to the experimental populations. The fit is better with the frequency dependent selection model.

Animals↗
PubMed1975

[The mutagenic effect of thioTEPA in laboratory mice. IV. The influence of genotype and sex on the frequency of induced chromosome aberrations in bone marrow cells].

In bone marrow cells of eleven genotypes of mice strain and sex variations in sensitivity to cytogenetic effect of thio-TEPA were studied. Strains 101/H, C57BL/6 and A/Sn were the more sensitive and F1 (CBAXC57BL/6) and F1 (C3HX101) were the more resistant to induction of chromosome damages. The rate of induced chromosome aberrations was correlated with the level of spontaneous chromosome damages in bone marrow cells (r=+/-0,893+/-0,02). From all strains males were more mutable than females. It is recommended to use C57BL/6 strain of mice male for genetic tests of chemicals by cytogenetic methods in vivo.

Animals↗
PubMed1977

[Aneuploidy and polyploidy in the bone marrow cells of minks of different genotypes, ages and fertility].

An analysis of aneuploidy and polyploidy in bone marrow cells of female minks of different genotype and age has shown that in young minks with unsatisfactory reproductive characteristics, and in old females, the frequency of aneuploid and polyploid cells is significantly higher as compared to that in minks having a good reproductive capacity. The increase in aneuploidy level takes place mainly in the form of hypoploidy, and an increase of the frequency of polyploid cells is accompanied by a parellel increase of the proportion of cells with a low degree of ploidy. A correlation between frequencies of appearance of aneuploid and polyploid cells in minks is observed (r = 0.69 +/- 0.27). On the basis of original and bibliographic data, a hypothesis on a genetically determined instability of karyotype in mutant minks is argumented.

Age Factors↗
PubMed1976

The genotypic distribution of relatives of homozygotes when consanguinity is present.

A correction is made to an expression given by Jacquard (1968, 1972a,b) for the genotypic distribution of a relative of a given homozygote when consanguinity is present. The correction will necessarily be small either if the allele present in the given homozygote has a frequency of near unity, or if the coefficient of inbreeding of the given homozygote is small.

Alleles↗
PubMed1978

A computer program for parenthood diagnosis within a family.

The knowledge of human polymorphism provides an efficient tool for parenthood diagnosis. This paper describes an algorithm to diagnose fatherhood within a family. In genetic research, the validation of human families is useful since at least 7% of the families have to be rejected from such studies. First, the algorithm verifies whether the phenotype of the presumed father is compatible with the genotypes of all children under the assumption of assured motherhood. An original index coding allows us to write simple algorithms: automatic creation of genetic elements, search of compatible genotypes of parentes and children. Finally, the algorithm calculates several indices used to estimate the likehood of the paternity of non-excluded man.

Computers↗