Maternal Half Research Articles

Use of microsatellite loci to classify individuals by relatedness.

This study investigates the use of microsatellite loci for estimating relatedness between individuals in wild, outbred, vertebrate populations. We measured allele frequencies at 20 unlinked, dinucleotide-repeat microsatellite loci in a population of wild mice (Mus musculus), and used these observed frequencies to generate the expected distributions of pairwise relatedness among full sib, half sib, and unrelated pairs of individuals, as would be estimated from the microsatellite data. In this population one should be able to discriminate between unrelated and full-sib dyads with at least 97% accuracy, and to discriminate half-sib pairs from unrelated pairs or from full-sib pairs with better than 80% accuracy. If one uses the criterion that parent-offspring pairs must share at least one allele per locus, then only 15% of full-sib pairs, 2% of half-sib pairs, and 0% of unrelated pairs in this population would qualify as potential parent-offspring pairs. We verified that the simulation results (which assume a random mating population in Hardy-Weinberg and linkage equilibrium) accurately predict results one would obtain from this population in real life by scoring laboratory-bred full- and half-sib families whose parents were wild-caught mice from the study population. We also investigated the effects of using different numbers of loci, or loci of different average heterozygosities (He), on misclassification frequencies. Both variables have strong effects on misclassification rate. For example, it requires almost twice as many loci of He = 0.62 to achieve the same accuracy as a given number of loci He = 0.75. Finally, we tested the ability of UPGMA clustering to identify family groups in our population. Clustering of allele matching scores among the offspring of four sets of independent maternal half sibships (four females, each mated to two different males) perfectly recovered the true family relationships.

SRVX, a sex reversing locus in Xp21.2?p22.11

Duplication within Xp21 causes female or intersexual development in human embryos with an XY chromosome complement. We have mapped the responsible gene, SRVX (sex reversal X), in XY-sex-reversed maternal half siblings who had inherited the duplication from their mother. The limited size of the duplication in our cases, relative to its extent in other similar cases, allows assignment of the SRVX locus to Xp21.2-->p22.11. We infer that SRVX is part of a pathway of sex-determining genes that includes SRY and SRA1, the latter recently assigned to chromosome 17q. If mutation of SRA1 or SRVX can reverse the sex of the XY fetus, this would explain why mutation within SRY is found only sporadically in women with XY gonadal dysgenesis.

Multiple mating and kin recognition by self-inspection

,uitipie mating by females with different males is widespread M in nature (e.g., among birds: Westneat et al. 1990; mammals: Ginsberg and Huck 1989; insects: Page 1986) and paternity ,exciusion analyses using genetic markers have revealed that broods are often sired by more than one male. Do individuals favor full siblings over maternal half siblings and, if so, how do they discriminate between them? These issues have been the subject of numerous investigations and considerable debate. In a recent issue of this journal, Alexander (1990) summarized the data and discussed (p. 273) “the extent to which social learning, especially without self-reference, can account for the kin recognition findings of different investigators with different organisms.” He argued that current information is most consistent with the hypothesis that direct recognition of kin occurs by a process of learning the physical attributes (phenotypes) of other family members and then comparing the phenotypes of individuals being discriminated to the remembered “template.” An alternative is that individuals learn their own phenotype and compare others to themselves. The latter mechanism was called the “armpit effect” by Dawkins (1982, p. 146) because an animal might conceivably obtain recognition cues by sniffing its own armpits, and “self-referent phenotype matching” by Holmes and Sherman (1982, 1983). Why is this apparently arcane issue interesting? As Hamilton (1987, p.

Analyse umweltbedingter und genetischer Einflüsse auf die Häufigkeit von Hüftgelenksdysplasie beim Deutschen Schäferhund

The importance of environmental and genetic influences on the frequency of hip dysplasia was studied in 10,595 German shepherd dogs. Systematic effects were analysed using mixed linear and mixed nonlinear threshold models. Following effects were regarded in the models applied: sire and mother of the dog as random effects, age at x-raying, sex, birth year and season of the x-rayed dogs, litter size, percentage of x-rayed dogs in each litter and sex ratio of the litter as fixed effects. Sire, mother, sex and age at x-raying showed significant influence on the occurrence of hip dysplasia. The heritability estimates in a hierarchical data design (sire, mother within sire) for the polychotomous trait hip dysplasia were for full sibs h2 = 0.30, for maternal half sibs h2 = 0, 48, and for paternal half sibs h2 = 0.11. Only the heritability estimates of the paternal half sibs seem to be reliable because kennel and breeder effects are confounded with the mother effect. Analysing the frequency of hip dysplasia as all-or-none traits, the heritability estimates were usually lowered by 50%. Selection programmes to reduce frequency of hip dysplasia can be improved if the estimation of breeding values with respect to environmental effects and frequency of hip dysplasia in all relatives will be implemented.

Toad tadpole kin recognition: recognition of half siblings and the role of maternal cues

In laboratory experiments, western toad (Bufo boreas) tadpoles preferentially associated with full siblings over paternal half siblings and with maternal half siblings over non-siblings. Tadpoles did not distinguish between full siblings and maternal half siblings or between paternal half siblings and non-siblings. These results suggest a maternal component to kin recognition. However, maternal half siblings were not preferred over paternal half siblings. Therefore, the effect of maternal cues may be complex. B. boreas tadpoles can probably use both direct and indirect familiarity to discriminate between kin classes.

FITNESS CONSEQUENCES OF MULTIPLE PATERNITY IN WILD RADISH, RAPHANUS SATIVUS.

In natural populations, wild radish plants typically mate with 6-8 pollen donors, and seeds of individual fruits are usually sired by 1-4 fathers. Since radish fruits are indehiscent and gravity-dispersed, progeny are most likely to compete with a mixture of full and half siblings. The fitness consequences of single and multiple paternity were investigated in a greenhouse experiment. Seeds of every possible cross in a 5 times 5 reciprocal diallel mating design were assigned to one of three competition regimes (four full siblings, four maternal half siblings, or four unrelated individuals per pot) or were grown as singletons. After 14 weeks, the aboveground biomass of all plants was harvested and oven-dried. The dry weight of singletons was more than three times that of progeny grown in competition, indicating that intraspecific competition had occurred. Full- and half-sib progenies did not differ in mean dry weight. Thus, there was no evidence that multiple paternity enhances this aspect of maternal fitness. However, the competition regime dramatically affected the coefficient of variation in dry weight of progeny within a pot. Weight hierarchies were much more pronounced in pots of half sibs and unrelated neighbors than in pots of full sibs. Also variance in dry weight attributable to sire was greatest in the half-sib and "unrelated neighbors" competition regimes. These results suggest that weight hierarchies reinforce genetic differences among the offspring.

Demonstration of Fabry's disease deposits in placenta

Involvement of the placenta by glycosphingolipid deposits in Fabry's disease has not been previously reported. We describe the presence of such deposits in the maternal half of a placenta obtained from a heterozygous carrier of the disease.

Estimation of Components of Variance and Covariance by Symmetric Differences Squared and Minimum Norm Quadratic Unbiased Estimation: a Comparison

Standard errors were obtained of four different estimators of components of variance and covariance applied to five specific data set designs. The designs were for estimating the genetic and environmental components of variance and covariance of a maternal model. The four estimators were symmetric differences squared (SDS), minimum norm quadratic unbiased estimation (MINQUE) with all prior values for the components of variance and covariance set to zero except for the environmental variance (MINQUE(0)), MINQUE with all prior values for the components of variance and covariance set to 1 (MINQUE(1)), and minimum variance quadratic unbiased estimation (MIVQUE). The standard errors of SDS, MINQUE(0), MINQUE(1), and MIVQUE estimates of variances due to direct and maternal additive effects of genes, covariance between direct and maternal additive effects of genes, variance due to environmental effects common to maternal half- and full-siblings and variance due to temporary environmental effects were computed for data sets consisting of 200 sets of Thompson's A or B design (1976), or 200 sets of Eisen's 1, 2, or 3 design (1967). Efficiency was computed as standard error of MIVQUE divided by standard error of SDS, MINQUE(0), or MINQUE(1). Symmetric differences squared weighted by the inverse of the environmental variance-covariance matrix (WSDS) is equivalent to MINQUE(0). Over all parameter sets, components estimated, and designs, the efficiency of MINQUE(1) ranged from .80 to .99, the efficiency of SDS ranged from .30 to .95 and the efficiency of MINQUE(0) ranged from .33 to .99. On the average, MINQUE(0) was more efficient than SDS and MINQUE(1) was more efficient than MINQUE(0). The efficiency of MINQUE(1) was insensitive to differences between the true components of variance and covariance and their prior values.

Regional variations in the levels of zinc, iron, copper, and calcium in the term human placenta

This study investigated the influence of the location of the sampling site during elemental analyses of 21 human term placentae. The levels of iron, zinc, copper and calcium in fetal membranes, umbilical cords and placental discs were measured by atomic absorption spectrophotometry and compared. The disc samples were obtained from central (peri-insertion and mid-disc fetal and maternal halves), and peripheral regions. Significant variations were found. Copper was present in highest level (17.2 ± 2.0 μg/g dry weight) in the fetal membranes. Calcium levels were highest (712 ± 47 μg/g dry weight) in the periphery of the placental disc. Iron levels were highest (558 ± 14 μg/γ dry weight) in the central regions of the disc. Zinc levels were lower (50.3 ± 1.4 μg/g dry weight) in the fetal half of the mid-disc regions than in the maternal half (56.0 ± 1.2 μg/g dry weight). This study demonstrates the importance of defining the location of the sampling site ins studies involving elemental analysis of the placenta.

Honey bee kin recognition: learning self and nestmate phenotypes

It is known that there is a genetic basis to the labelling of individuals for kin recognition in the honey bee, Apis mellifera. This study shows that individual workers reared in total isolation are able to discriminate between their full sisters and maternal half sisters. When individuals were reared with a half sister, recognition of their own patritype persisted, together with a comparable awareness of the patritype of their half sisters. Workers, when reared in mixed patritype groups of 10, showed no tendency to discriminate between full and half sisters, i.e. they appeared to learn both nestmate patritypes equally well. However, the labelling phenotypes of individuals reared together became more uniform, possibly through the transfer of substances during trophallaxis and mutual grooming. Workers exposed to 10 patritypes from their full sister patriline were more likely to accept an unfamiliar full sister than workers exposed to only five. Finally, workers reared in the hive appeared to retain an ability to discriminate their own patritype; i.e., even though the hive consisted of two worker patritypes, they discriminated between unfamiliar full and half sisters that had been reared under the same controlled conditions in an incubator.

Immunochemical localization of vitamin D-dependent calcium-binding protein in mouse placenta and yolk sac.

A 10,000-dalton calcium-binding protein (10-kd CaBP) has been described in the placentae and yolk sacs of rats and mice. This protein is similar or identical to vitamin D-dependent intestinal CaBP and these proteins have been implicated in the molecular mechanisms of intestinal calcium absorption and transplacental calcium transport. Using an antiserum to the purified 10-kd rat intestinal CaBP, the localization of CaBP in the 16-17-day mouse yolk sac and placenta was studied immunocytochemically with peroxidase-antiperoxidase labelling and quantified by radial immunodiffusion. A high concentration of immunolabelling was observed in the endodermal cells of the intraplacental yolk sac lining the sinuses of Duval. The columnar endodermal cells lining one side of the endodermal sinuses adjacent to fetal vessels contained most of the immunoreactive label. Quantitation by radial immunodiffusion demonstrated a 5.5-fold higher concentration of CaBP in the portion of the placenta containing most of the intraplacental yolk sac than in the maternal half of the placenta. This demonstration of a 10-kd CaBP within the intraplacental yolk sac suggests this protein functions to facilitate placental calcium transport and is the first study which directly supports the hypothesis of a functional role for the sinuses of Duval in calcium transport.

Effect of ignoring full sib relationships when making half sib estimates of heritability

Heritability estimated from sire family variance components, ignoring dams, pools conventional paternal and maternal half sib estimates, in a way which is biased upward, and sub-optimal for minimizing the sampling variance. Standard error of a sire family estimate will be smaller than that of the equivalent paternal half sib estimate, but not as small as that of an estimate obtained by optimal pooling of paternal and maternal half sib estimates. If only additive genetic variance components are significant, the bias may be removed by use of a computed average genetic relationship for sire families, in place of a nominal R = 0.25. Average genetic relationship may be computed from mean and variance of dam family size within sire families. If dominance, epistatic, or maternal components are significant, this simple correction is not appropriate. In situations likely to be encountered in large domestic species such as sheep and cattle (dam family size small and uniform) bias will be negligible. The method could be useful where cost of dam identification is a limiting factor.

PATH ANALYSIS OF ENVIRONMENTAL AND GENETIC INFLUENCES ON BLOOD PRESSURE

Familial aggregation of a trait (determined by the intraclass correlation coefficient) may result from genetic influence or from environment common to a household. The authors used path analysis to separate aggregation into the proportion of population variability due to genetic influence (h2 = heritability) and the proportion due to environment common to a household (c2). They used data from full siblings and maternal half siblings, aged two to 18 years, from Bogalusa, Louisiana, a biracial community. The statistically significant aggregation they found could be explained by either h2 or c2 except for two cases: systolic measurement in the pooled (black and white) sample requires h2; diastolic measurement in the white sample requires c2. The authors present a simplified explanation of the techniques they used.

Cytogenetics of White <i>Allium</i>

During studies over genetic parameters of the local red onion bulbs, certain progenies of maternal half sib families segregated a few white bulbs. Some of these bulbs bred true to the white colour and though they were sexually normal and fertile, a few exhibited seed sterility. These steriles when cultured separately were found to be either translocation heterozygotes or desynaptic strains. In plants a single meiotic ring involving either a few or the entire zygotic chromosome complement is known. But the formation of regular independent rings, each composed of 4 chromosomes, and involving the whole zygotic complement is unknown so far. This has been found in some of these white Allium cepa strains and represents a new type of translocation system existent in the plant kingdom. Predominance of either rings or chains or their equal proportion was observed in the various clones, each configuration being specific and constant for each clone. The predominant occurrence of rings in certain clones could be because the sites of chromosomal breakages are closer to centromere and interchange pieces are more or less equal in length. But where the interstitial segment is short, exchanged pieces are relatively small thus resulting in chain configuration formations.Though pollen fertility ranged from 9-22 per cent, seed sterility was complete in these translocation heterozygotes. When the clones were selfed or intercrossed among each other or crossed as seed or pollen parent with normal fertile Allium cepa, no seeds were set, indicating thereby the existence of male and female sterility in these clones. Genetic control of these regular and specific translocations has been postulated. Since such a type of translocations involving regularly 2 heterozygotes, each of the entire genome, are extremely rare and occur in a very low frequency, their control seems under recessive genes.

Predicting Daughter Milk Production from Dam Index

Abstract First lactations in Dairy Herd Improvement Associations from 10,349 registered Holsteins in Iowa, Kanasa, and Missouri were used to evaluate the usefulness of Estimated Average Transmitting Ability of dams to predict milk production of their future duaghters where dam and daughter were in the same herd. This index estimates half the genetic worth of a cow from her records and records of her dam, daughters, paternal and maternal half sisters. Correlation of dam's index with daughter deviated first lactation milk yield was .18 where .20 was expected. Linear regression of daughter first lactation deviated yield on dam index was 1.15, which differed from 1.00. Quadratic and cubic regressions were not significant, but daughters of the lowest dams produced more milk than expected. Deviated yield of daughter first lactation was regressed simultaneously on groups of relatives in the dam's index. Weights for cow were larger than expected, and weights for dam were smaller than expected. Multiple correlations indicated dams and maternal sisters contributed less than expected to accuracy of predicting daughter yield.

The nerves of the umbilical cord in man and the rat.

AbstractA thiocholine technique was used to visualize nerves in human and rat umbilical cords. The allantoic part of the rat umbilical cord was found to be separate from the vitelline part of the cord and its vessels were not innervated. However, acetylcholinesterase‐positive nerves formed a plexus around the vessels of the vitelline part of the 21‐day rat umbilical cord. These nerves displayed fusiform swellings and terminated as simple endings close to the yolk sac wall. The findings suggest that the vitelline circulation in the rat may function under neural control.An investigation of full‐term human umbilical cords revealed extrafetal acetylcholinesterase‐positive nerves. Nerve bundles passed from the fetus into the cord and split into a plexus. Beaded nerve terminals were found about 15–20 cm from the fetus. Some of these endings touched the media of the vein; others ended freely in the cord substance between the arteries and the vein. There were no periarterial terminals and no nerves were found in the maternal half of the cord.The free nerve endings in the human cord may have been sensory, since they made no terminal effector contact. However, it should be noted that similar terminals touched the media of the umbilical vein. The endings described could be sensory receptors for the sphincter of the ductus venosus that controls venous return from the fetus.

Genetic and environmental causes of variation in birth weight of Black Bengal goats

SUMMARYAn investigation on the different environmental and genetic causes of variation in the birth weight of Black Bengal goats was conducted at the Central Livestock Research-cum-Breeding Station, Haringhata, India. The data consisted of 1375 birth weight records of kids from 284 does and 20 bucks during the period from 1955 to 1961. The goats were maintained under standard farm management throughout the period.Year had significant effect on birth weight, while the effect of season was insignificant. The interaction was, however, significant. Male kids were significantly heavier at birth than the females. Age of dam and litter size also caused significant variation in birth weight of kids.From paternal half-sib analysis the heritability of birth weight was estimated to be 0·01. Full sib and maternal half sib analyses estimated the maternal environment common to litter mates to account for 60 % of the variance, out of which 25 % were due to permanent differences between dams. The remaining 39 % were attributed to individual environment, including most of the non-additive genetic variance. The heritability of maternal environment was estimated to be 0·2.The partial correlation coefficient between birth weight of kids and post-kidding body weight of their dam, independent of litter size and age of dam, was 0·175. Thus, body size of dam, as indicated by post kidding body weight, did not reveal much information about maternal environment.

Familial monotropic pituitary gonadotropin insufficiency.

Abstract Three siblings, 2 females and 1 male, had eunuchoidism with selective insufficiency of pituitary gonadotropin. A fourth sibling, a male, probably was affected, but death precluded definitive study. A maternal half sister was normal. There were no distinctive somatic features except absence of secondary sex characteristics and relatively long extremities in proportino to height. No other associated congenital defects were observed. Chromosome constitutions were normal for their phenotypes. Consanguineous parental mating between second cousins once removed was probably causative. Evidence for autosomal recessive inheritance is presented.

A Selection Index for Fat Production in Dairy Cattle Utilizing the Fat Yields of the Cow and Her Close Relatives

Summary An index for intraherd selection for fat production was derived, utilizing the fat yields of the cow and those of her dam, daughters, maternal half sisters, and paternal half sisters. Statistics to construct the index were computed from 23,330 lactation fat yields of 12,405 Jersey cows on HIR test. The intraherd statistics needed to construct the index were: repeatability, 0.412; correlation between maternal half sisters, 0.073; correlation between paternal half sisters, 0.120; and heritability, 0.201. Herd differences accounted for 39% of the total variance. Within herds the year-to-year variation in things which affected all cows alike accounted for 8% of the variance. Progress to be expected by using the index for selections would generally be about 1.10 to 1.15 times faster than by making selections on the cow's own performance alone. The exact ratio for a specific situation would depend on the number of records on the individual, on the number and kinds of relatives, and on the amount of information available about each.