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PubMed1990

Inbreeding effects on bilateral asymmetry of dermatoglyphic patterns.

Bilateral correlations are higher and bilateral variances within individuals smaller in the samples of inbred individuals than in matched control groups of the same sex for pattern intensities on fingers in four series of data and also for pattern intensities on palms, toes, and soles and the palmer main line indices in the data collected from a Muslin population of West Bengal. This trend is not apparent in two series of data from the Yanadi tribe, in which the inbred and noninbred samples are not controlled for random variation of genes and environment. Increased variances between individuals and changes in means and distributions of the traits in the inbred samples of the matched data indicate some influence of homozygosity of genes for the traits on their asymmetry. The reduced variability of asymmetry of the traits in the inbred cannot be explained by homozygosity of genes for either directional or absolute asymmetry. One possible explanation is that heterozygotes for these dermatoglyphic triats are more responsive to environmental stress than homozygotes and/or increased selection in the homozygotes against genetic disorders associated with dermatoglyphic asymmetry may reduce the variability of such asymmetry.

Analysis of Variance↗
PubMed2006

Evolution of the hemiascomycete yeasts: on life styles and the importance of inbreeding.

The term 'breeding system' is used to describe the morphological and behavioural aspects of the sexual life cycle of a species. The yeast breeding system provides three alternatives that enable hapoids to return to the diploid state that is necessary for meiosis: mating of unrelated haploids (amphimixis), mating between spores from the same tetrad (intratetrad mating, automixis) and mother daughter mating upon mating type switching (haplo-selfing). The frequency of specific mating events affects the level of heterozygosity present in individuals and the genetic diversity of populations. This review discusses the reproductive strategies of yeasts, in particular S. cerevisiae (Bakers' or budding yeast). Emphasis is put on intratetrad mating, its implication for diversity, and how the particular genome structure could have evolved to ensure the preservation of a high degree of heterozygosity in conjunction with frequent intratetrad matings. I also discuss how the ability of yeast to control the number of spores that are formed accounts for high intratetrad mating rates and for enhanced transmission of genomic variation. I extend the discussion to natural genetic variation and propose that a high level of plasticity is inherent in the yeast breeding system, which may allow variation of the breeding behaviour in accordance with the needs imposed by the environment.

Animals↗
PubMed1989

Linkage analysis with inbreeding.

For computational reasons, linkage analysis of highly inbred pedigrees is often performed under the assumption that spouse pairs are genetically unrelated. A formulation of the likelihood of a pedigree which takes into account all of the genealogical information omega, for an arbitrary relationship between a pair of spouses, is proposed. Lod scores at a recombination fraction of 0 for an inbred three-member nuclear family are presented.

Child↗
PubMed1981

Inbreeding and the genetic control of nondisjunction.

We have studied the frequency of trisomics in newly formed zygotes and the proportion of trisomics, k, coming from consanguineous marriages by assuming that recessive genes at a single locus or multiple loci are responsible for the induction of nondisjunction. For mitotic nondisjunction, the value of k increases as the magnitude of consanguinity of the parents increases, but the opposite relationship holds for meiotic nondisjunction. Therefore, it is important to distinguish mitotic and meiotic types in the genetic study of nondisjunction. This seems to be one of the simplest tests for detecting the genetic control of nondisjunction.

Consanguinity↗
PubMed1986

Inbreeding considerations in a REM sleep model for rat swimming activity.

Over the past few years, our laboratory group has elaborated a repeated measures rat swimming test. It provides an animal base for showing that the REM sleep mechanism is important to both emotional responsiveness and environmental adaptations. All of that work has been done with Sprague-Dawley rats obtained from a local supplier. Work done with two European rat stocks (by researchers in France and The Netherlands) shows general agreement with our own. In this presentation, we directly compare rats derived from an English vendor's Sprague-Dawley stock with the U.S. based Sprague-Dawley stock which we have been using. We also make strain comparisons via the F344 and the Long Evans strains. Although the literature has numerous examples of swimming test differences between inbred and wild rat stocks, strain difference effects have not been reported. We report that there are significant differences attributable to inbred strain but not to vendor on this measure.

Animals↗
PubMed2002

Inbreeding and true seed in tetrasomic potato. III. Early selection for seedling vigor in open-pollinated populations.

Tuber yield in open-pollinated (OP) offspring of potato cultivars appears to be correlated with the proportion of hybrids within each population. OP true potato seed (TPS) from ten selected clones was tested in an experiment at two Peruvian locations, San Ramón (mid-altitude warm tropics) and Huancayo (highland cool tropics), to investigate the early selection effect on OP populations. Another experiment in La Molina (dry coast) was included to confirm the results from these other two locations. The results clearly showed that plant survival, tuber yield and berry number can be increased by a strong early selection. Likewise, the results suggested that the most-promising OP offspring for TPS production could be derived from tetraploid clones with a high rate of outcrossing. This experiment demonstrates that high tuber yield may be obtained in OP TPS cultivars with little effort, using early selection for seedling vigor in the nursery. Genetic interpretation of this response to early selection indicates that both the intensity of selection and non-additive genetic variation for tuber yield account for these observed gains.

Journal Article↗
PubMed2003

Possible olfaction-based mechanisms in human kin recognition and inbreeding avoidance.

Three studies explored kin recognition through olfaction. In Study I, adults (N=22) were tested for ability to identify the odors of themselves; their mother; their father; a sister; a brother; a familiar, unrelated individual; and a stranger. Acquaintances were identified as accurately as biological kin, implicating an association mechanism. However, biological kin were often confused, implicating phenotypic matching. Same-sex kin were confused more than opposite-sex kin, but mainly when same-sex kin had odors of similar intensity. Study II implicated phenotypic matching. Mothers (N=18) could identify their biological children but not their stepchildren. The preadolescent children (N=37) identified their full siblings but not half-siblings or stepsiblings. Thus, olfactory cues may help mediate favoritism of blood relatives. In Study III, mutual olfactory aversion occurred only in the father-daughter and brother-sister nuclear family relationships. Recognition occurred between opposite-sex siblings but not same-sex siblings. Thus, olfaction may help mediate the development of incest avoidance during childhood (the Westermarck effect).

Adult↗