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PubMed2004

Context-dependent autonomous self-fertilization yields reproductive assurance and mixed mating.

The evolution of self-fertilization in hermaphrodites is opposed by costs that decrease the value of self progeny relative to that of outcross progeny. However, self-fertilization is common in plants; 20% are highly selfing and 33% are intermediate between selfing and outcrossing. Darwin proposed an adaptive benefit of self-pollination in providing reproductive assurance when outcrossing is impossible. Moreover, if outcross pollen receipt is inconsistent within or between years, these conditions likewise favour self-pollination, and this can result in a mixture of self and outcross seed production (mixed mating). Despite wide acceptance, the reproductive assurance hypothesis has lacked the support of complete empirical evidence to show that variable pollination can create both the ecological and genetic conditions favouring self-pollination. We recently showed in Collinsia verna that during periods of infrequent pollinator visits, autonomous self-pollination boosted seed output per flower, the key ecological condition. Here we show low inbreeding depression and marker-based estimates of selfing, demonstrating that when the pollination environment in wild populations necessitates reproductive assurance, selfing rates increase. We provide a complete demonstration of reproductive assurance under variable pollination environments and mechanistically link reproductive assurance to intermediate selfing rates through mixed mating.

Breeding↗
PubMed2006

A risk index for early node-negative breast cancer.

BACKGROUND: This study compared the application of the St Gallen 2001 classification with a risk index developed at the New South Wales Breast Cancer Institute (BCI Index) for women with node-negative breast cancer treated without adjuvant systemic therapy. METHODS: The BCI risk categories were constructed by identifying combinations of prognostic indicators that produced homogeneous low-, intermediate- and high-risk groups using the same variables as in the St Gallen classification. RESULTS: The BCI low-risk category consisted of women aged 35 years or more with a grade 1 oestrogen receptor (ER)-positive tumour 20 mm or less in diameter, or with a grade 2 ER-positive tumour of 15 mm or less. This category constituted 40.1 per cent of patients, with a 10-year distant relapse-free survival (DRFS) rate of 97.2 per cent. The BCI intermediate-risk category included women aged 35 years or more with a grade 2 ER-positive tumour of diameter 16-20 mm, or a grade 1 or 2 ER-negative tumour measuring 15 mm or less, and comprised 12.1 per cent of the women, with a 10-year DRFS rate of 88 per cent. The high-risk category comprised 47.7 per cent of women, with a 10-year DRFS rate of 68.4 per cent. CONCLUSION: If confirmed in other data sets, the BCI Index may be used to identify women at low risk of distant relapse (2.8 per cent at 10 years) who are unlikely to benefit from adjuvant systemic therapy, and women at intermediate risk of distant relapse (12 per cent at 10 years) in whom the benefit of adjuvant systemic therapy is small.

Adult↗
PubMed1995

Experiments on second intermediate fish host related cercarial transmission of the eyefluke Diplostomum spathaceum into rainbow trout (Oncorhynchus mykiss).

The effect of host variables such as size and density, on the transmission of cercariae of Diplostomum spathaceum (Rudolphi, 1819) into a second intermediate fish host, rainbow trout, Oncorhynchus mykiss (Walbaum), was studied quantitatively in laboratory experiments under varying exposure conditions. Differences in the number of established metacercariae were noted in differently sized fish exposed singly to the same number of cercariae and in water volumes related to the body surface area of the host. When exposed (1) singly in an equal water volume or, (2) simultaneously in the same tank, no differences in recovery of metacercariae per fish were found between "small" and "large" hosts. The latter observation is valid for three water volumes tested using the same number of cercariae per host. No significant difference in metacercarial infection was revealed in similar sized fish exposed at different host densities. It appears that transmission is more influenced by cercarial density (number of cercariae per water volume) and fish size than by fish density. These experimental findings support the view that cercarial infection of fish occurs by chance, presumably mainly in the gill region. Accordingly, in the field, individual fish size and cercarial density rather than fish population density, prevail in parasite transmission from snail to fish. This is of interest in coastal areas heated by cooling water, where fish growth and fish population density are enhanced.

Animals↗
PubMed2005

Effect of estradiol valerate on ovarian follicle dynamics and superovulatory response in progestin-treated cattle.

Three experiments evaluated the effects of estradiol valerate (EV) on ovarian follicular and CL dynamics, intervals to estrus and ovulation, and superovulatory response in cattle. Experiment 1 compared the efficacy of two norgestomet ear implants (Crestar and Syncro-Mate B; SMB) for 9 d (with PGF at implant removal), combined with either 5 mg estradiol-17beta and 100 mg progesterone (EP) or 5 mg EV and 3mg norgestomet (EN) im at the time of implant insertion on CL diameter and follicular wave dynamics. Ovaries were monitored by ultrasonography. There was no effect of norgestomet implant. Diameter of the CL decreased following EN treatment (P < 0.01). Mean (+/- S.D.) day of follicular wave emergence (FWE) was earlier (P < 0.0001) and less variable (P < 0.0001) in EP- (3.6 +/- 0.5 d) than in EN- (5.7 +/- 1.5 d) treated heifers. Intervals from implant removal to estrus (P < 0.001) and ovulation (P < 0.01) were shorter in EN- (45.7 +/- 11.7 and 74.3 +/- 12.6 h, respectively) than in EP- (56.4 +/- 14.1 and 83.3 +/- 17.0 h, respectively) treated heifers. Experiment 2 compared the efficacy of EP versus EN in synchronizing FWE for superovulation in SMB-implanted cows. At random stages of the estrous cycle, Holstein cows (n = 78) received two SMB implants (Day 0) and were randomly assigned to receive EN on Day 0 or EP on Day 1. Folltropin-V treatments were initiated on the evening of Day 5, with PGF in the morning and evening of Day 8, when SMB were removed. Cows were inseminated after the onset of estrus and embryos were recovered 7 d later. Non-lactating cows had more CL (16.7 +/- 11.3 versus 8.3 +/- 4.9) and total ova/embryos (14.7 +/- 9.5 versus 7.9 +/- 4.6) than lactating cows (P < 0.05). EP-treated cows tended (P = 0.09) to yield more transferable embryos (5.6 +/- 5.2) than EN-treated cows (4.0 +/- 3.7). Experiment 3 compared the effect of dose of EV on ovarian follicle and CL growth profiles and synchrony of estrus and ovulation in CIDR-treated beef cows (n = 43). At random stages of the estrous cycle (Day 0), cows received a CIDR and no further treatment (Control), or an injection of 1, 2, or 5 mg im of EV. On Day 7, CIDR were removed and cows received PGF. Follicular wave emergence occurred within 7 d in 7/10 Control cows and 31/32 EV-treated cows (P < 0.05). In responding cows, interval from treatment to FWE was longer (P < 0.05) in those treated with 5 mg EV (4.8 +/- 1.2 d) than in those treated with 1 mg (3.2 +/- 0.9 d) or 2 mg (3.4 +/- 0.8 d) EV, while Control cows were intermediate (3.8 +/- 2.0 d). Diameter of the dominant follicle was smaller (P < 0.05) at CIDR removal and tended (P = 0.08) to be smaller just prior to ovulation in the 5 mg EV group (8.5 +/- 2.2 and 13.2 +/- 0.6 mm, respectively) than in the Control (11.8 +/- 4.6 and 15.5 +/- 2.9 mm, respectively) or 1mg EV (11.7 +/- 2.5 and 15.1 +/- 2.2 mm, respectively) groups, with the 2mg EV group (10.7 +/- 1.5 and 14.3 +/- 1.7 mm, respectively) intermediate. Diameter of the dominant follicle at CIDR removal was less variable (P < 0.01) in the 2 and 5mg EV groups than in the Control group, and intermediate in the 1mg EV group. In summary, treatment with 5mg EV resulted in a longer and more variable interval to follicular wave emergence than treatment with 5mg estradiol-17beta, which affected preovulatory dominant follicle size following progestin removal, and may have also affected superstimulatory response in Holstein cows. Additionally, 5 mg EV appeared to induce luteolysis in heifers, reducing the interval to ovulation following norgestomet removal. Conversely, intervals to, and synchrony of, follicular wave emergence, estrus and ovulation following treatment with 1 or 2 mg EV suggested that reduced doses of EV may be more useful for the synchronization of follicular wave emergence in progestogen-treated cattle.

Animals↗
PubMed2004

Smoking onset in adolescence: a person-centered analysis with time-varying predictors.

Predictions from smoking-specific versus contextual models of smoking onset were tested with data from a 4-wave sample with 1,364 adolescents. Predictor variables were derived from stress-coping theory, social influence theory, and problem-behavior theory. In addition to groups of abstainers and experimenters, cluster analysis of smoking data indicated 3 groups who showed onset either in 7th grade (early onset), 9th grade (intermediate onset), or 10th grade (late onset). Almost all study variables discriminated the smoking groups from the abstainers. The onset groups were discriminated by Group X Time interactions showing differential changes in predictors (increases in risk factors and declines in protective factors), which occurred just prior to onset. The results generally support a contextual model of the onset process.

Adolescent↗
PubMed1999

Circadian patterns of heart rate variability in normals, chronic stable angina and diabetes mellitus.

The purpose of our investigation was to compare circadian patterns of heart rate variability as assessed by 24-h ambulatory electrocardiographic (ECG) recordings in normal subjects, chronic stable angina, and Type 1 diabetes mellitus. The study population consisted of three groups: 12 normal subjects, 23 chronic angina patients, and 23 Type 1 diabetics. For purposes of analyzing circadian variation, the ECG recordings were divided into daytime (08:00-00.00 h) and night-time (00:00-08:00 h) periods. Analysis was performed for all time and frequency domain measures of heart rate variability, attempting to identify differences in day-to-night variability among these three groups. All time domain parameters except standard deviation of all 5-min mean RR intervals, and all frequency domain indices maintain significant circadian variations (P<0.0001), with the greatest day to night variation seen in normals, the least in diabetics, and intermediate values in chronic angina. These changes in heart rate variability circadian rhythms reflect significant reductions in cardiac parasympathetic activity with the most marked reduction in nocturnal vagal activity. Given the circadian pattern of myocardial ischemia and infarction, these data suggest that quantification of the magnitude of circadian variation in heart rate variability may have the potential to further risk stratify chronic angina and diabetes for future cardiac events.

Adult↗
PubMed1998

Psychological adjustment variables as predictors of mortality among nursing home residents.

Mortality over a 4-year period was examined in relation to self-esteem, depression, life satisfaction, and meaning in life in a nonclinical sample of 129 intermediate-care nursing home residents. Survival was associated with the psychological adjustment variables, and the effect persisted after statistically controlling for age, sex, and physical health. Self-evaluations (self-esteem and depression) were stronger predictors of mortality than were general life evaluations (life satisfaction and meaning in life). Comparisons with previous studies suggest conditions under which psychological variables are likely to be associated with mortality.

Adaptation, Psychological↗
PubMed1986

Compensation point and isotopic characteristics of c(3)/c(4) intermediates and hybrids in panicum.

Leaf CO(2) compensation points and stable hydrogen, oxygen and carbon isotope ratios were determined for Panicum species including C(3)/C(4) intermediate photosynthesis plants, hybrids between C(3)/C(4) intermediates and C(3) plants, C(3) and C(4) plants in the Panicum genus as well as several other C(3) and C(4) plants. C(3) plants had the highest compensation points, followed by hybrids, C(3)/C(4) intermediates, and C(4) plants. delta(13)C values of cellulose nitrate and saponifiable lipids from C(4) plants were about 10 per thousand higher than those observed for cellulose nitrate and saponifiable lipids of C(3)/C(4) intermediates, hybrids, and C(3) plants. Oxygen isotope ratios of cellulose as well as those of leaf water were similar for all plants. There was substantial variability in the deltaD values of cellulose nitrate among the plants studied. In contrast, such variability was not observed in deltaD values of water distilled from the leaves, nor in the deltaD values of the saponifiable lipids. Variability in deltaD values of cellulose nitrate from C(3)/C(4) intermediates, hybrids, C(3), and C(4) plants is due to fractionations occurring during biochemical reactions specific to leaf carbohydrate metabolism.

Journal Article↗
PubMed1987

Centralized obesity and cardiovascular disease risk in Mexican Americans.

The association between body fat distribution patterns and cardiovascular disease risk variables (high density lipoprotein (HDL) cholesterol, total cholesterol, diastolic and systolic blood pressures, and fasting blood glucose levels) was sought in a sample of Mexican American adults who were studied during 1981-1983 in Starr County, Texas. In the sample, all diabetics were excluded to see whether centralized obesity carried any risk for cardiovascular disease independent of diabetes. A component of centralized body fat distribution was identified through the use of principal components analysis of five skinfold measurements, which included the upper and lower extremities and trunk areas. The centralized obese were compared with generalized (peripheral) obese and nonobese controls in four subgroups of the population: younger and older adult males and females. The means of all cardiovascular risk variables were in a direction indicating that the centralized obese were significantly at greater risk than nonobese controls (in particular, HDL cholesterol, total cholesterol, and blood glucose levels). The generalized obese differed from the centralized obese in having significantly lower blood glucose levels, and tended to be intermediate between centralized obese and nonobese controls in the other variables. The data confirm that centralized obesity as defined by a linear combination of skinfold measures works in the same way as the waist-to-hip circumference ratio in describing a body build factor which heightens the risk of cardiovascular disease in the obese independent of the clinical diabetic state.

Adult↗
PubMed2004

[Mesangial glomerulonephritis and intermediate uveitis].

Uveitis in children are less frequent than in adults. Their prognosis is variable because it may be found as an isolated and idiophatic condition or in association with definite clinical entities. The associated noninfectious diseases with predominantly renal involvement are tubulointerstitial nephritis and uveitis syndrome (TINU syndrome), mesangial glomerulonephritis isolated or in association with Behçet's disease. A case of 14-years-old girl with intermediate uveitis (pars planitis) and mesangial glomerulonephritis is presented. The ocular symptoms was eye redness and ocular pain and she has snow-banks in pars plana. She showed microscopic hematuria and intermitent proteinuria that increased during the ocular clinical exacerbation. Renal biopsy revealed both mild mesangial matrix increase and mesangial celullarity with normal tubulointerstitial structure and mesangial deposition of IgA and IgG immunoglobulins. This case is de first pediatric patient report in the literature with intermediate uveitis and mesangial glomerulonephritis with immune deposition. Mesangial glomerulonephritis were observed in patients whit Behçet disease, known etiological cause of uveitis in adults and children. These findings may suggest that uveitis and glomerulonephritis have common immunological pathogenesis including circulatory immune complexes. In uveitis patients, screening for associated extra-ocular and renal manifestations is mandatory and should have careful long-term follow-up with regular systemic evaluation.

Adolescent↗
PubMed2006

Oxygen uptake-to-delivery relationship: a way to assess adequate flow.

Invasive and noninvasive monitoring facilitates clinical evaluation when resuscitating patients with complex haemodynamic disorders. If the macrocirculation is to be stable, then it must adapt to blood flow or blood flow must be optimized. The objective of flow monitoring is to assist with matching observed oxygen consumption (VO2) to pathophysiological needs. If an adequate balance cannot be maintained then dysoxia occurs. In this review we propose a simple schema for global reasoning; we discuss the limitations of VO2 and arterial oxygen delivery (DaO2) assessment; and we address concerns about increasing DaO2 to supranormal values or targeting pre-established levels of DaO2, cardiac output, or mixed venous oxygen saturation. All of these haemodynamic variables are interrelated and limited by physiological and/or pathological processes. A unique global challenge, and one that is of great prognostic interest, is to achieve rapid matching between observed and needed VO2--no more and no less. However, measuring or calculating these two variables at the bedside remains difficult. In practice, we propose a distinction between three situations. Clinical and blood lactate clearance improvements can limit investigations in simple cases. Intermediate cases may be managed by continuous monitoring of VO2-related variables such as DaO2, cardiac output, or mixed venous oxygen saturation. In more complex cases, three methods can help to estimate the needed VO2 level: comparison with expected values from past physiological studies; analysis of the relationship between VO2 and oxygen delivery; and use of computer software to integrate the preceding two methods.

Blood Circulation↗
PubMed2003

Correlative coherence analysis: variation from intrinsic and extrinsic sources in competing populations.

The concept of the correlation between two signals is generalized to the correlative coherence of a set of n signals by introducing a Shannon-Weaver-type measure of the entropy of the normalized eigenvalues of the n-dimensional correlation matrix associated with the set of signals. Properties of this measure are stated for canonical cases. The measure is then used to evaluate which subsets of a particular set of n signals are more or less coherent. This set of signals comprises extrinsic, stochastic resource inputs and the population trajectories obtained from simulations of a discrete time model of competing biological populations driven by these resource inputs. The analysis reveals that, at low levels of competition, the correlative coherence of the combined system of intrinsic population and extrinsic resource variables is relatively low, but increases with increasing variation in the resources. Further, at intermediate and high competition levels, the correlative coherence depends more strongly on competition than entrainment of stochasticity in the extrinsic resource variables. Density dependence has the effect of amplifying variation in noise only when this variation is relatively large. Also, chaotic systems appear to be entrained by sufficiently noisy environmental inputs.

Analysis of Variance↗
PubMed2001

Partially folded intermediates as critical precursors of light chain amyloid fibrils and amorphous aggregates.

Light chain, or AL, amyloidosis is a pathological condition arising from systemic extracellular deposition of monoclonal immunoglobulin light chain variable domains in the form of insoluble amyloid fibrils, especially in the kidneys. Substantial evidence suggests that amyloid fibril formation from native proteins occurs via a conformational change leading to a partially folded intermediate conformation, whose subsequent association is a key step in fibrillation. In the present investigation, we have examined the properties of a recombinant amyloidogenic light chain variable domain, SMA, to determine whether partially folded intermediates can be detected and correlated with aggregation. The results from spectroscopic and hydrodynamic measurements, including far- and near-UV circular dichroism, FTIR, NMR, and intrinsic tryptophan fluorescence and small-angle X-ray scattering, reveal the build-up of two partially folded intermediate conformational states as the pH is decreased (low pH destabilized the protein and accelerated the kinetics of aggregation). A relatively nativelike intermediate, I(N), was observed between pH 4 and 6, with little loss of secondary structure, but with significant tertiary structure changes and enhanced ANS binding, indicating exposed hydrophobic surfaces. At pH below 3, we observed a relatively unfolded, but compact, intermediate, I(U), which was characterized by decreased tertiary and secondary structure. The I(U) intermediate readily forms amyloid fibrils, whereas I(N) preferentially leads to amorphous aggregates. Except at pH 2, where negligible amorphous aggregate is formed, the amorphous aggregates formed significantly more rapidly than the fibrils. This is the first indication that different partially folded intermediates may be responsible for different aggregation pathways (amorphous and fibrillar). The data support the hypothesis that amyloid fibril formation involves the ordered self-assembly of partially folded species that are critical soluble precursors of fibrils.

Amyloid↗
PubMed1999

Novel mutation in the myelin protein zero gene in a family with intermediate hereditary motor and sensory neuropathy.

OBJECTIVES: To determine the molecular basis for autosomal dominant intermediate hereditary motor and sensory neuropathy (HMSN) in a four generation family. The gene defects in families with intermediate HMSN are not known, but it has been suggested that most have X linked HMSN. METHODS: All participating family members were examined clinically. Genomic DNA was obtained from 10 affected and seven unaffected members. Linkage analysis for the known HMSN loci was first performed. Mutations in the peripheral myelin protein zero gene (PMP0) were sought in two affected members, using one unaffected member for comparison, by amplification of the six exons of the gene followed by single strand conformation polymorphism (SSCP) analysis, dideoxy fingerprinting (ddF), and sequencing. Subsequently, the mutation was screened for in all affected and unaffected members in the family using Alu I digestion and in 100 unrelated control subjects using "snap back" SSCP analysis. Sequencing of cDNA from a sural nerve biopsy from an affected member was also performed. RESULTS: The clinical phenotype was of variable severity, with motor nerve conduction velocities in the intermediate range. Linkage to PMP0 was demonstrated. Analysis of genomic DNA and cDNA for PMP0 identified a novel codon 35 GAC to TAC mutation. The mutation produces an inferred amino acid change of aspartate to tyrosine at codon six of the processed protein (Asp6Tyr) in the extracellular domain and was present in all affected family members but not in 100 unrelated controls. CONCLUSIONS: The present findings further extend the range of phenotypes associated with PMP0 mutations and indicate that families with "intermediate" HMSN need not necessarily be X-linked as previously suggested.

Adult↗
PubMed1995

The mechanism of Escherichia coli tryptophan indole-lyase: substituent effects on steady-state and pre-steady-state kinetic parameters for aryl-substituted tryptophan derivatives.

We have examined the reaction of Escherichia coli tryptophan indole-lyase with fluoro, chloro, methyl and hydroxytryptophans using steady-state kinetics, rapid-scanning and single wavelength stopped-flow spectrophotometry, and rapid chemical quench methods. All of the 16 tryptophan derivatives examined are substrates for alpha, beta-elimination catalyzed by tryptophan indole-lyase. The steady-state kinetic parameter, kcat/Km, did not show a consistent trend with the steric bulk of the substituent, but Km increased for larger substituents. Rapid-scanning stopped-flow spectra show that all tryptophan analogues undergo covalent reaction with the pyridoxal-5'-phosphate cofactor to give equilibrating mixtures of external aldimine and quinonoid intermediates, but the relative amounts of each intermediate are strongly dependent on the nature and position of the substituent. The dissociation constants for external aldimine formation, Kd, obtained from single-wavelength stopped-flow experiments decreased for most substituted tryptophans, which suggests that part of the binding energy is derived from hydrophobic interactions between the enzyme and the indole ring of tryptophan. In contrast, the rate constants of quinonoid intermediate formation and reprotonation and of indole elimination were quite variable, depending on the position and the nature of the substituent. Overall, 6-substituted tryptophans have the most consistent reactivity, which indicates that there may be space in the enzyme active site near the 6-position. There is a good linear correlation between log (kcat/Km) and log (kf/Kd) (apparent second order rate constant for quinonoid intermediate formation), with a slope of 0.66. This suggests that quinonoid intermediate formation contributes only about 66% of the activation energy for the reaction, and thus a later step in the reaction must be partially rate-limiting. Rapid chemical quench experiments demonstrate a 'burst' of indole in the reaction of L-tryptophan under single turnover conditions, confirming that a step subsequent to the elimination is partially rate-determining. In contrast, 5-methyl-L-tryptophan does not exhibit a significant 'burst', suggesting that 5-methylindole elimination is nearly completely rate-determining. These results support the proposed mechanism and demonstrate that there are significant effects of aryl substituents on the distribution of covalent intermediates and on the rate-determining step in the alpha, beta-elimination reaction catalyzed by E. coli tryptophan indole-lyase.

Binding Sites↗
PubMed2000

Synthesis and analytical characterization of the sodium salt of heptakis(2-O-methyl-3,6-di-O-sulfo)cyclomaltoheptaose, a chiral resolving agent candidate for capillary electrophoresis.

A pure, single isomer, strong electrolyte chiral resolving agent candidate for capillary electrophoresis, the sodium salt of heptakis(2-O-methyl-3,6-di-O-sulfo)cyclomaltoheptaose has been synthesized on the 100-g scale, in greater than 97% purity, through heptakis(2,6-di-O-tert-butyldimethylsilyl)cyclomaltoheptaose, heptakis(2-O-methyl-3,6-di-O-tert-butyldimethylsilyl)cyclomaltohep taose and heptakis(2-O-methyl)cyclomaltoheptaose intermediates. The structural identity of each intermediate and the final product was conclusively established by high-resolution MALDI-TOF mass spectrometry, variable-temperature 1H and 13C NMR spectroscopy and X-ray crystallography. The purity of each intermediate and the final product was determined by gradient high-performance liquid chromatography (HPLC) and indirect UV detection capillary electrophoresis.

Chromatography, High Pressure Liquid↗
PubMed1996

Familial paroxysmal dystonic choreoathetosis revisited.

A case of familial paroxysmal dystonic choreoathetosis (PDC) documented by video/EEG monitoring is described. The father of the proband is affected by exertional cramping but not PDC, lending support to the previous hypothesis that exertional cramping may represent a "forme fruste" or the incomplete expression of PDC. Other family members affected by PDC are women, with exercise-induced cramping alone found in two men. Two of the women report prolonged exertion as a precipitant of lengthy spells consistent with typical PDC rather than the previously described "intermediate," exercise-induced form of PDC. Exertional cramping in families affected by PDC may represent the variable expression of the "dystonia gene" in male members. Conversely, exercise-induced PDC, both of the intermediate and longer form described here, may have a predilection to manifest in women.

Adult↗
PubMed2001

[Computer modeling of joint selection response of MGE patterns and a polygenic system].

Using computer simulation, selection response of three genome patterns--polygenes, mobile genetic elements (MGEs), and labels of identity by origin (LIOs)--were studied. In each generation of selection, variability of each pattern type was described by on UPGMA tree. Stringent positive truncation selection on an additive polygenic trait and recombination between segments of the genetic map were considered. MGEs were classified into three groups: modifiers (enhancers) of the polygenic expression, markers, and independent copies. It was shown that at generations 30 to 40, 95-96% and 70-80% of respectively enforced and non-enforced active polygenic alleles were fixed (2-3% and 16-17% lost). In all generations, Hkn < or = Dkn of the length of the maximal route along the tree. At the same time, modifier MGEs were fixed for 85-88% (lost for 11-12%); marker MGEs, for 60-70 (lost for 21-25%); and independent copies, for 30-40 (lost for 50-60%). The behavior of independent MGE copies was generally consistent with the predictions of the genetic drift theory, modifier MGEs behaved similarly to the modified polygenes, and marker MGEs exhibited intermediate properties. The LIO patterns showed rapid homozygotization: their variability dropped dramatically between generations 10 and 30. In F50, the final consensus pattern of polygenes included 16 out of 18 enforced and 18 out of 21 non-enforced polygenic alleles. The fixation/loss ratios were 16:3 for modifier MGEs, 15:6 for marker MGEs, and 25:28 (with 7 polymorphic) for independent copies. The LIO consensus pattern contained 13 out of 100 original markers, which formed 26 fragments of one to ten map segments in size; 21 fragments contained active polygenic alleles, and 14 of them had also modifier MGEs. Recombinational shuffling of patterns was not completed. In the course of selection, active polygenic alleles take along adjacent segments, including those containing modifier MGEs and markers. These constitute the conservative part of all consensus patterns while the remaining segments are random.

Computer Simulation↗