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Results for “artificial selection”

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PubMed2004

Similarity in young women's eating attitudes: self-selected versus artificially constructed groups.

OBJECTIVE: The current study explored similarity (in terms of eating attitudes, depression, and anxiety) among new versus established groups of young women. METHOD: Three hundred and thirty-two female students (living in 80 apartments) participated in the study. They were either living in a newly formed "no-choice" apartment or a "choice" apartment where they had chosen their housemates. All participants completed the Eating Disorders Inventory and the Hospital Anxiety and Depression Scale. The groups were compared using similarity indices (showing attitude spread per apartment). RESULTS: Consistent with our hypothesis, the choice groups held more similar eating-related attitudes and depression levels than the no-choice groups. Specifically, the choice groups were significantly more similar in their levels of ineffectiveness, interpersonal distrust, and social insecurity. DISCUSSION: In a similar way to depression, eating attitudes may be shared among relatively close groups of women.

Adolescent↗
PubMed1991

Effects of artificial stabilizing selection on Drosophila populations subjected to directional selection for another trait.

Stabilizing selection for a set of morphometric wing traits was combined with directional selection for the increased expression of radius incompletus (ri) mutation of Drosophila melanogaster. Three experimental regimes were used: directional and stabilizing selection (stabilized lines); directional selection (unstabilized lines); no selection (controls). Response to selection for ri expression was similar in all selected lines but variation of this character was higher in the unstabilized lines compared to the stabilized ones. The competitive indices measured after termination of selection did not significantly differ under different treatments while fluctuating asymmetry was significantly lower in stabilized than in unstabilized lines. The possible causes of these differences are discussed.

Animals↗
PubMed1992

Differential effects of neonatal testosterone treatment on aggression in two selection lines of mice.

Selection lines of mice, artificially selected for aggression based upon the attack latency score (ALS), were used. In order to determine the relative contribution of neonatal testosterone (T) in the development of aggression, we vary the plasma-T level in males of both selection lines on the day of birth. At 14 weeks the ALS was measured. Neonatal T treatment results in a reduction of aggression in the long attack latency (LAL) line, whereas aggressive behaviour of the short attack latency (SAL) line is not affected. Both selection lines show reduction in testicular weight, although the total amount of T-producing Leydig cells was not affected. Neonatal T may cause a permanent reduction in aggressive behaviour in in the LAL line only, probably due to differential appearance of critical periods. It is suggested that the difference in aggressive behaviour between SAL and LAL selection lines is due to a prenatally determined difference in neonatal T sensitivity of the brain.

Aggression↗
PubMed2003

Toward protein-cleaving catalytic drugs: artificial protease selective for myoglobin.

A protein-cleaving catalyst highly selective for a disease-related protein can be used as a catalytic drug. As the first protein-cleaving catalyst selective for a protein substrate, a catalyst for myoglobin (Mb) was designed by attaching the Cu(II) or Co(III) complex of cyclen to a binding site searched by a combinatorial method using peptide nucleic acid monomers as building units. Various linkers were inserted between the catalytic Co(III) center and the binding site of the Mb-cleaving catalyst. Kinetic data revealed catalytic turnover of the Mb cleavage by the Cu(II) or Co(III) complex. MALDI-TOF MS revealed cleavage of the polypeptide backbone of Mb at selected positions. N-Terminal sequencing of the cleavage products identified the cleavage site and provided evidence for the hydrolytic nature of the Mb cleavage. Various chelating ligands were tested as the ligand for the Co(III) center of the Mb-cleaving catalyst. Among the nine chelating ligands examined, only cyclen and its triaza-monooxo analogue manifested catalytic activity.

Binding Sites↗
PubMed2005

Platinum(II) complex as an artificial peptidase: selective cleavage of peptides and a protein by cis-[Pt(en)(H2O)2]2+ ion under ultraviolet and microwave irradiation.

Two synthetic peptides were completely cleaved by the cis-[Pt(en)(H2O)2]2+ (en is ethylenediamine) complex at pH 2.5 under thermal heating at 60 degrees C in a selective way: only the amide bonds involving the carboxylic group of the methionine residue, i.e., the Met-Z bonds (where the residue Z has a noncoordinating side chain), were hydrolyzed. Under irradiation at 300 nm, the rate constants for these cleavage reactions were approximately doubled, but side reactions occurred. Under microwave irradiation, the rate constants were increased 2-3 times at 60 degrees C and ca. 7 times at 100 degrees C, and no side reactions were detected. Microwave irradiation similarly accelerated the complete and selective cleavage of Met-Z bonds in cytochrome c at 60 degrees C in comparison with this cleavage under thermal heating, again without detected side reactions. The microwave-assisted cleavage of peptides and proteins by the platinum(II) reagent holds promise in proteomics and other biotechnological applications.

Cations, Divalent↗
PubMed2006

Segregation analysis of blood oxygen saturation in broilers suggests a major gene influence on ascites.

1. Blood oxygen saturation (SaO) is a potential indicator trait for resistance to ascites in chickens. 2. The objective of the study was to investigate the genetic architecture of SaO in a meat-type chicken line reared in commercial conditions. 3. Data were collected over 15 generations of selection and were divided into two data sets on the basis of a change in recording age from 6 to 5 weeks of age, approximately halfway through the period. The resulting pedigrees comprised in excess of 90,000 birds each and, on average, 12% of these birds had SaO records. 4. Segregation analyses of SaO were carried out assuming a mixed inheritance model that included a major locus segregating in a polygenic background. 5. The analyses suggest that a major gene is involved in the genetic control of SaO in this line. The putative gene acts in a dominant fashion and has an additive effect of around 0.90 sigma(p), equivalent to a predicted difference in SaO between the two homozygous classes of more than 10%. The frequency of the allele that increases SaO changed from 0.53 to 0.65 from the first to the second set of data, consistent with selection on SaO scores. 6. Using estimated genotype probabilities at the putative major locus, we inferred that it acts in an overdominant fashion on body weight and fleshing score. If the low SaO allele leads to susceptibility to ascites, its combined effects are consistent with it being maintained in the population by a balance of natural selection on fitness nad artificial selection on growth and carcase traits. 7. Even with selection on both SaO and growth traits, the combined genotypic effects would make it difficult to remove the unfavourable low-SaO allele by means of traditional selection without the use of genetic markers.

Animals↗
PubMed2024

Evolutionary consequences of domestication on the selective effects of new amino acid changing mutations in canids.

The domestication of wild canids led to dogs no longer living in the wild but instead residing alongside humans. Extreme changes in behavior and diet associated with domestication may have led to the relaxation of the selective pressure on traits that may be less important in the domesticated context. Thus, here we hypothesize that strongly deleterious mutations may have become less deleterious in domesticated populations. We test this hypothesis by estimating the distribution of fitness effects (DFE) for new amino acid changing mutations using whole-genome sequence data from 24 gray wolves and 61 breed dogs. We find that the DFE is strikingly similar across canids, with 26-28% of new amino acid changing mutations being neutral/nearly neutral (|s| < 1e-5), and 41-48% under strong purifying selection (|s| > 1e-2). Our results are robust to different model assumptions suggesting that the DFE is stable across short evolutionary timescales, even in the face of putative drastic changes in the selective pressure caused by artificial selection during domestication and breed formation. On par with previous works describing DFE evolution, our data indicate that the DFE of amino acid changing mutations depends more strongly on genome structure and organismal characteristics, and less so on shifting selective pressures or environmental factors. Given the constant DFE and previous data showing that genetic variants that differentiate wolf and dog populations are enriched in regulatory elements, we speculate that domestication may have had a larger impact on regulatory variation than on amino acid changing mutations.

Journal Article↗
PubMed1999

Effects of genetic selection and voluntary activity on the medial gastrocnemius muscle in house mice.

In a previous study, we found that in house mice both genetic selection (10 generations of artificial selection for high voluntary activity on running wheels) and access to running wheels (7-8 weeks) elicited a modest increase in maximal oxygen consumption. Based on these results, we hypothesized that genetic selection would affect the changes in endurance and oxidative capacity of the medial gastrocnemius (MG) muscle induced by wheel access (training response). Wheel access increased the isotonic endurance of the MG in both genetically selected and random-bred (control) mice. However, this exercise-induced improvement in isotonic endurance of the MG was similar between genetically selected and control mice. Wheel access also increased the succinate dehydrogenase activity of MG muscle fibers in both selected and control lines. However, this exercise-induced increase in succinate dehydrogenase activity was comparable between genetically selected and control animals. Taken together, these results indicate that the modest increase in maximal oxygen consumption associated with genetic selection is not reflected by the training-induced changes in oxidative capacity and endurance of MG muscle fibers.

Animals↗
PubMed1990

[Immunogenetic characteristics of the gene fund of Kakhetian swine and dynamics of population parameters in several generations].

Some peculiarities of gene fund and dynamics of populational characters of the oldest in Europe Kakhetian (Georgian) pigs were investigated during 18 years (10 generations). Genetic peculiarity of the aboriginal species populations in conditions of intensive pressure of natural selection and relatively weak artificial selection was determined with the help of codominant alleles of the blood groups E system. Considerable qualitative and quantitative differences were detected between Kakhetian pigs and all subspecies of European boars and domestic pigs of cultured breeds studied. Kakhetian pigs are strongly similar to wild boar, as concerns their morpho-physiological and behavioral characteristics. However, the assumption that they originated from Romanian (Caucasian) wild boar by direct domestication, without hybridization, is wrong, since they have alleles which are never found in European wild boars. The results of comparative study of Kakhetian and other domesticated and wild pig forms characteristics makes it possible to suppose that the presence in Kakhetian pigs gene fund of some alleles of East Asian origin is due to a certain participation of the Large White and Mangalica breeds in their phylogenesis. The two latter breeds, in their turn, obtained these alleles as a result of two waves of pig importation in Europe from the South-East Asia (on the eve of a.d. and about 150-200 years ago). This is indirectly confirmed by historical and zootechnical data.

Alleles↗