Biomedical subjects

A Tremblay

Publications and source records attributed to A Tremblay.

At least 73 records · Page 4Linked to original sources

PubMed2001

Elevated intramyocellular lipid concentration in obese subjects is not reduced after diet and exercise training.

To determine the effects of weight loss on intramyocellular energy substrates, vastus lateralis muscle biopsies were taken from six obese subjects (body mass index 34 +/- 5 kg/m(2)) before, after 15 wk of energy restriction (ER; -700 kcal/day), and after a further average 20.7 +/- 1.6 wk of endurance training plus low-fat diet (ET-LFD). Body weight fell from 100 +/- 6 to 89 +/- 6 kg during ER and to 84 +/- 4 kg after ET-LFD. Lipids and glycogen were histochemically measured in type I, IIA, and IIB fibers. Total muscle glycogen content (MGC; per 100 fibers) decreased after ER [from 72 +/- 13 to 55 +/- 8 arbitrary units (AU)]. A similar but not significant decrease was seen in total muscle lipid content (MLC; 14 +/- 5 to 9 +/- 1 AU). After ET-LFD, MGC returned to initial values (74 +/- 8 AU), and MLC approached near-initial values (12 +/- 3 AU). Individual fiber lipid concentration did not change throughout the protocol in all fiber types, whereas glycogen concentration increased after ET-LFD. The training effects of ET-LFD were measured as increasing activities of key mitochondrial enzymes. Although total muscle energy reserves can be reduced after weight loss, their concentration within individual myofibers remains elevated. Weight loss does not appear sufficient to correct the potential detrimental effects of high intracellular lipid concentrations.

Adult↗

PubMed2001

Age-related differences in messenger ribonucleic acid expression of key proteins involved in adipose cell differentiation and metabolism.

This study was performed to compare the expression of key proteins [lipoprotein lipase (LPL), hormone-sensitive lipase (HSL), complement 3 (C3), and peroxisome proliferator-stimulated receptor-gamma (PPAR gamma)] involved in sc abdominal adipose tissue (AT) metabolism of young (n = 13) vs. middle-aged (n = 16) men. The sc abdominal AT-LPL activity as well as fat cell lipolysis were also measured in both groups of men. Young and middle-aged men displayed similar body weight and sc abdominal fat accumulation, measured by computed tomography. However, middle-aged men were characterized by a higher percent body fat (28 +/- 5% vs. 22 +/- 7%; P < 0.05) than young subjects. No difference between groups was observed in sc abdominal adipose tissue LPL activity. On the other hand, maximal lipolytic responses of sc abdominal adipocytes to isoproterenol (beta-adrenergic agonist) or to postadrenoceptor agents such as dibutyryl cAMP, forskolin, and theophylline were lower in middle-aged than in young men (P < 0.05). AT-LPL messenger ribonucleic acid (mRNA) levels were similar regardless of the subject's age. However, HSL, C3, and PPAR gamma mRNA levels were higher in middle-aged than in young individuals (P < 0.01-0.05). After correction for percent body fat, only HSL and C3 mRNA levels remained significantly different between groups (P < 0.05). Taken together, these results suggest that aging has an effect on the up-regulation of HSL and C3 mRNA levels, whereas PPAR gamma expression seems to be related mainly to increased adiposity.

Abdomen↗

PubMed2001

Deterioration of the metabolic risk profile in women. Respective contributions of impaired glucose tolerance and visceral fat accumulation.

OBJECTIVE: To determine whether the impaired glucose tolerance (IGT) state contributes to the deterioration of the metabolic profile in women after taking into account the contribution of visceral adipose tissue (AT) accumulation, as measured by computed tomography. RESEARCH DESIGN AND METHODS: We studied 203 women with normal glucose tolerance (NGT) and 46 women with IGT, defined as a glycemia between 7.8 and 11.1 mmol/l measured 2 h after a 75-g oral glucose load. RESULTS: Women with IGT were characterized by a higher visceral AT accumulation and by higher concentrations of fasting plasma glucose, insulin, and C-peptide as well as by higher plasma concentrations of cholesterol, triglycerides, and apolipoprotein B (apoB) and by greater cholesterol-to-HDL-cholesterol ratio, reduced LDL peak particle size, lower HDL-cholesterol and HDL2-cholesterol concentrations, and higher blood pressure (P < 0.01) than women with NGT. When we matched 27 pairs of women for visceral AT and fat mass as well as for menopausal status, differences previously found in LDL-cholesterol, LDL peak particle size, HDL-cholesterol, and HDL2-cholesterol concentrations as well as in the cholesterol-to-HDL-cholesterol ratio and blood pressure were eliminated, whereas triglyceride concentrations remained significantly higher in women with IGT. CONCLUSIONS: A high visceral AT accumulation is a major factor involved in the deterioration of many metabolic variables in women with IGT, with the notable exception of triglyceride concentrations, which remained significantly different between women with NGT and women with IGT after adjustment for visceral fat.

Adipose Tissue↗

PubMed2001

[Determination of the potassium balances in diary cows and the examination of daily and lactation period-associated variations.

The objectives of this study were to evaluate a method of determining the internal and external potassium balances in dairy cows and to determine daily and lactation period-associated variations of these balances. Ingested potassium, milk potassium concentration (LK) and potassium urinary fractional clearance (FeK) defined the potassium external balance. Serum (SK) and red blood cell (CIEK) potassium concentrations defined the potassium internal balance. Whole blood, urine, and milk were collected at different times of the day from 19 cows, grouped in 5 lactation periods. Significant differences were observed for LK between lactation periods. Significant variations occurred during the day for CIEK, LK, and FeK. Thus, in order to monitor potassium balances during a time period, samples should be collected at the same time each day. This method of determining both potassium balances simultaneously could be useful in the study of the bovine hypokalemia syndrome.

Animals↗

PubMed2001

Reduced HDL particle size as an additional feature of the atherogenic dyslipidemia of abdominal obesity.

Reduced plasma HDL cholesterol concentration has been associated with an increased risk of coronary heart disease. However, a low HDL cholesterol concentration is usually not observed as an isolated disorder because this condition is often accompanied by additional metabolic alterations. The objective of this study was to document the relevance of assessing HDL particle size as another feature of the atherogenic dyslipidemia found among subjects with visceral obesity and insulin resistance. For that purpose, an average HDL particle size was computed by calculating an integrated HDL particle size using nondenaturing 4-30% gradient gel electrophoresis. Potential associations between this average HDL particle size versus morphometric and metabolic features of visceral obesity were examined in a sample of 238 men. Results of this study indicated that HDL particle size was a significant correlate of several features of an atherogenic dyslipidemic profile such as increased plasma TG, decreased HDL cholesterol, high apolipoprotein B, elevated cholesterol/HDL cholesterol ratio, and small LDL particles as well as increased levels of visceral adipose tissue (AT) (0.33 < or = absolute value of r < or = 0.61, P < 0.0001). Thus, men with large HDL particles had a more favorable plasma lipoprotein-lipid profile compared with those with smaller HDL particles. Furthermore, men with large HDL particles were also characterized by reduced overall adiposity and lower levels of visceral AT as well as reduced insulinemic-glycemic responses to an oral glucose load. In conclusion, small HDL particle size appears to represent another feature of the high TG- low HDL cholesterol dyslipidemia found in viscerally obese subjects characterized by hyperinsulinemia.

Abdomen↗

PubMed2000

Contribution of visceral obesity to the deterioration of the metabolic risk profile in men with impaired glucose tolerance.

AIMS/HYPOTHESIS: Impaired glucose tolerance is associated with metabolic alterations which increase cardiovascular disease risk. The contribution of hyperglycaemia to this increased risk is, however, not clear. Abdominal obesity is often observed in subjects with impaired glucose tolerance; our objective was therefore to find the contribution of visceral adipose tissue to the deterioration of the metabolic risk profile noted in subjects with impaired glucose tolerance. METHODS: We studied 284 men with a normal glucose tolerance and 66 men with impaired glucose tolerance which was defined as a glycaemia between 7.8 and 11.1 mmol/l 2 h after a 75-g glucose load. RESULTS: Men with impaired glucose tolerance had more visceral adipose tissue and higher concentrations of plasma glucose and insulin in the fasting state and following a 75-g oral glucose load than men with a normal glucose tolerance. They also had higher concentrations of plasma cholesterol, triglycerides, apolipoprotein B and lower concentrations of HDL-cholesterol as well as higher cholesterol:HDL-cholesterol ratios than men with a normal glucose tolerance. The two groups of men were then compared after a statistical adjustment for the amount of visceral adipose tissue. Although men with impaired glucose tolerance still had higher fasting plasma glucose and insulin concentrations after the adjustment for visceral adipose tissue, differences in all the variables of the lipid-lipoprotein profile were eliminated. CONCLUSION/INTERPRETATION: Visceral adipose tissue accumulation is an important factor in the deterioration of the plasma lipid-lipoprotein noted in men with impaired glucose tolerance.

Abdomen↗

PubMed2000

The small, dense LDL phenotype as a correlate of postprandial lipemia in men.

The atherogenic dyslipidemia of the insulin resistance syndrome is characterized by hypertriglyceridemia (hyperTG), elevated apolipoprotein (apo) B levels, reduced high-density lipoprotein (HDL) cholesterol concentrations and by an increased proportion of small, dense low-density lipoprotein (LDL) particles. Although the hyperTG-low HDL cholesterol dyslipidemia has been associated with an impaired clearance of dietary fat, the contribution of the small, dense LDL phenotype as an independent predictor of postprandial triglyceride (TG) clearance remains uncertain. We have therefore compared the postprandial TG response among three subgroups of men characterized by small, intermediate or large LDL particles in a total sample of 69 men (mean age +/- SD; 45.1 +/- 10.5 years). To identify men with small versus large LDL particles, the first (LDL peak particle diameter < 251.9 A) and the third (> 257.6 A) tertiles of the distribution of LDL particle diameters were used as cutoff points. Men with small, dense LDL particles had the expected fasting dyslipidemic profile (high TG-low HDL cholesterol levels) compared to men with large, buoyant LDL particles. The oral lipid tolerance test revealed that men with small, dense LDL particles had significantly higher total-, large-, and medium-TG-rich lipoprotein (TRL) responses to a fatty meal than men with large LDL particles (P < 0.03). In addition, within a subgroup of normolipidemic men (TG < 2.3 mmol/l and HDL cholesterol > 0.9 mmol/l), those with small, dense LDL particles had higher levels of total-, medium- and small-TRL responses compared to men with large, buoyant LDL particles (P < 0.05). Moreover, normotriglyceridemic men with small, dense LDL had higher levels of small-TRLs measured 8 h after the ingestion of the fat meal (P < 0.05) compared to normolipidemic men with large, buoyant LDL particles. Results of the present study suggest that the dense LDL phenotype may be an additional fasting marker of an exaggerated postprandial TG response and of an impaired clearance of TRLs.

Adult↗

PubMed2000

[Weight reduction through physical exercise and diet--how much is enough and is too much possible?].

Presently available literature reveals that a combination of approach has the potential to induce a body weight loss and favor weight maintenance in a reduced-obese state while also normalizing the metabolic profile of these individuals. Further weight loss is thus no longer justified and might be harmful to weight maintenance and health although these individuals could still be diagnosed as obese according to actual classifying criteria for defining obesity.

Anti-Obesity Agents↗

PubMed2000

No association between resting metabolic rate or respiratory exchange ratio and subsequent changes in body mass and fatness: 5-1/2 year follow-up of the Québec family study.

OBJECTIVE: To investigate the relationships between resting metabolic rate (RMR) and respiratory exchange ratio (RER) and subsequent changes in body size and fatness. DESIGN: Prospective longitudinal observational study. PARTICIPANTS: A sample of 147 participants (76 males, 71 females) 18-68 y of age were followed for approximately 5-1/2 y. MEASURES: At baseline, post-absorptive RMR and RER were determined by indirect calorimetry and adjusted for the effects of age, body mass and subcutaneous fatness using regression procedures. Indicators of body size and fatness included body mass, waist circumference, and the sum of six skinfolds. Changes in these indicators (delta scores) were adjusted for age and length of the follow-up period using regression. RESULTS: Correlations between baseline RMR, RER and subsequent changes in the indicators of body fatness were uniformly low and not significant (range -0.05-0.16). Further, Cox proportional hazards regression analyses indicated that neither RMR nor RER were significant predictors of gains in body mass, waist circumference, or the sum of six skinfolds. CONCLUSIONS: There is no association between RMR or RER and changes in indicators of body size and fatness over 5(1/2) y of follow-up in this sample. European Journal of Clinical Nutrition (2000) 54, 610-614

Adipose Tissue↗

PubMed2000

Hyperleptinemia is more closely associated with adipose cell hypertrophy than with adipose tissue hyperplasia.

OBJECTIVES: To investigate the relationships of fat cell weight (FCW) as well as of estimated total adipose cell number to fasting plasma leptin concentration. DESIGN: Cross-sectional correlational study. SUBJECTS: A sample of 63 men (mean age+/-s.d.: 36+/-4 y) and 42 premenopausal women (35+/-5 y). MEASUREMENTS: Adipose tissue (AT) biopsies were obtained in order to determine FCW as well as estimated adipose cell number. Fasting plasma leptin and insulin concentrations as well as various fatness and body fat distribution variables (underwater weighing and computed tomography) were also measured. RESULTS: In both genders, mean FCW as well as the estimated adipose cell number were significantly correlated with body fatness and AT distribution variables (0.41</=r</=0.84). Larger abdominal (P<0.005) and femoral (P<0.0001) FCW were found in women than in men. This gender difference in adipose cell size was associated with increased leptin concentrations in women compared with men. In both genders, increased abdominal FCW was associated with higher plasma leptin concentrations (men: r=0.38, P<0.005 and women: r=0.55, P<0.0001). However, the association between femoral FCW and leptinemia was only significant in women (r=0.45, P<0.005). Contrary to women, plasma leptin concentrations were associated with estimated adipose cell number in men (r=0.59, P<0.0001). Multiple regression analyses revealed that gender (43.3%), mean FCW (16.2%) and the estimated adipose cell number (10.1%) were significant predictors of fasting leptinemia. CONCLUSIONS: Results of the present study indicate that in men and women, adipose cell hypertrophy is associated with increased plasma leptin concentrations. This finding provides further support to the observation that adipose tissue leptin secretion may be regulated, at least to a certain extent, by adipocyte size. Thus, the present study suggests that the higher plasma leptin concentrations found in women than in men could be partly explained by the well documented gender difference in adipose cell size and number.

Adipocytes↗

PubMed2000

Appetite after weight loss by energy restriction and a low-fat diet-exercise follow-up.

OBJECTIVE: The aim of the present study was to determine the impact of weight loss on appetite as measured by visual analog scale (VAS). METHODS: Seventeen subjects (10 men and seven women) took part in a 15 week weight loss program which consisted of drug therapy (fenfluramine 60 mg/day) or placebo coupled to an energy restriction (-2930 kJ/day; phase 1) followed by an 18 week low-fat diet-exercise follow-up (phase 2). Subjects were given a standardized breakfast before and after phase 1 as well as after phase 2. Individuals were asked to fill out VAS before and at 0, 10, 20, 30, 40, 50 and 60 min after this test meal. Blood samples were drawn before the meal and at 0, 30 and 60 min postprandially and analyzed for glucose and insulin. Fasting plasma cortisol and leptin were also determined. RESULTS: An increase in the fasting desire to eat, hunger and prospective food consumption (PFC) was observed after phase 1 and to an even greater extent after phase 2 in both men and women. In the fasting state, positive correlations were observed between changes in the desire to eat (r=0.76; P<0.05) as well as changes of PFC (r=0. 82; P<0.05) and changes in cortisol at the end of phase 1 for women. In response to phase 1, statistically significant correlations were found between changes of hunger (r=0.64; P<0.05) and desire to eat (r=0.67; P<0.05) as measured by AUC in response to the meal and changes of fasting plasma cortisol in men. The most consistent predictor of changes of baseline desire to eat (r=0.68 P<0.05), fullness (r=-0.78, P<0.05) and PFC (r=0.91, P<0.01) during phase 2 was the change in fasting cortisol in men. Changes of fullness were also associated with changes of fasting leptin in men (r=0.68; P<0. 05) during phase 2. CONCLUSION: These results suggest that weight loss is accompanied by an increase of baseline appetite in both men and women and that the most consistent predictor of these changes in appetite seems to be changes in fasting plasma cortisol.

Adult↗

PubMed2000

Body weight loss increases plasma and adipose tissue concentrations of potentially toxic pollutants in obese individuals.

BACKGROUND: While there appears to be a consensus among scientists and clinicians that body weight loss reduces the risk of several chronic diseases, these apparently favourable effects should be balanced against any potentially harmful side effect of weight loss. In this regard, weight loss has been shown to produce an increase in blood concentration of potentially toxic organochlorine pollutants in animals that can cause prejudice to health, but human data are lacking. METHODS: Thirty-nine obese individuals were subjected to a hypocaloric diet during 15 weeks. Blood and subcutaneous adipose tissue samples were analysed before and after treatment for 26 organochlorine compounds. A control group consisting of 57 women of similar mean age was also formed in order to compare plasma concentrations. RESULTS: Organochlorine pollutants were found in every subject and all 19 compounds detected had their plasma concentration increased following treatment (mean body weight loss 9.5 kg), 15 of which were statistically significant. When compared with a control group, five compounds increased significantly. These observations persisted after an 18 week low-fat diet/exercise program follow-up. Increases were correlated with body weight loss (-0.3 > or = r > or = -0.6, P<0.05) and adipose tissue analyses yielded similar results, as their concentration of organochlorine compounds increased following treatment. CONCLUSION: Body weight loss increases plasma and subcutaneous adipose tissue concentrations of organochlorine pesticides and PCBs in obese subjects. These results raise concerns about an undesired and potentially harmful side effect of weight loss in some obese patients who seem to be at greater risk of health problems than leaner subjects since they show higher organochlorine body burden.

Adipose Tissue↗

PubMed2000

beta-adrenoceptor-stimulated lipolysis of subcutaneous abdominal adipocytes as a determinant of fat oxidation in obese men.

BACKGROUND: To verify whether an impaired lipolytic capacity of subcutaneous adipocytes may contribute to low rate of fat oxidation. DESIGN: Relationships between adipose tissue lipolysis of subcutaneous (subc) abdominal and femoral isolated adipocytes and respiratory quotient (RQ) were investigated in 20 obese men (age: 44 +/- 5 years; means +/- SD) studied in a fasting state. RESULTS: Maximal isoproterenol-induced lipolysis was greater in subcutaneous abdominal than in femoral fat cells even if glycerol release was corrected for variation in cell surface area (P < 0.01). On the other hand, no regional variation was observed in the adipose cell lipolytic responses to postadrenoceptor agents such as dibutyryl-cyclic AMP, forskolin and theophylline. Maximal isoproterenol-induced lipolysis of subc abdominal, but not of femoral adipocytes, was inversely related to RQ (r = - 0.61; P < 0. 01) and positively associated to fat oxidation (r = 0.57; P < 0.01). These relationships were independent of possible confounding factors such as fat mass, fat-free mass, waist girth and subc abdominal adipose tissue accumulation assessed by computed tomography, as maximal isoproterenol-induced lipolysis of subcutaneous abdominal adipocytes was the only variable retained as a significant predictor of RQ levels (38% of variance) and of fat oxidation (30% of variance). CONCLUSION: These results suggest that adipose tissue lipolytic activity of subc abdominal adipocytes acts as a determinant of fat oxidation in obese men.

Abdomen↗

PubMed2000

Leptin receptor Gln223Arg variant is associated with a cluster of metabolic abnormalities in response to long-term overfeeding.

OBJECTIVES: The role of the leptin receptor (LEPR) gene Gln223Arg polymorphism on the metabolic and body composition changes in response to overfeeding was studied. SUBJECTS: Twelve pairs of male monozygotic twins ate a 4.2 MJ day-1 energy surplus, 6 days week-1, during a period of 100 days. RESULTS: Overfeeding induced a significantly greater increase in glucose (P = 0.001 for percentage change) and insulin (P = 0.038) areas under the curve during oral glucose tolerance tests (OGTTs) in the GlnGln (n = 10) than in the GlnArg/ArgArg (n = 14) subjects. In addition, the GlnGln genotype was associated with a greater increase in plasma levels of leptin (P = 0.037) and total triglycerides (P = 0.003), as well as a greater decrease in high-density lipoprotein cholesterol (P = 0.010), than for the combined GlnArg/ArgArg genotypes. Body composition changes were not different between the genotypes. CONCLUSIONS: We conclude that the GlnGln subjects of the LEPR gene polymorphism are more susceptible to metabolic abnormalities when they are exposed to long-term positive energy balance. These findings provide new information on the genetic basis of individual differences in response to chronically elevated food intake.

Adult↗

PubMed2000

Outbreak of cutaneous larva migrans in a group of travellers.

We describe an outbreak of cutaneous larva migrans (CLM) in a group of 140 holidaymakers to a resort in Barbados and the index case. methods A two-page questionnaire was mailed to holidaymakers and 90% responded. results 25.4% of respondents developed a rash consistent with CLM. Risk factors for developing the illness were younger age and less frequent use of protective footwear while walking to the beach. Patients had difficulty in obtaining a correct diagnosis during their initial medical consultation and in obtaining medication from pharmacies. Efficacious treatments were oral and topical thiabendazole. conclusions CLM can occur in a large proportion of people exposed to contaminated soil or sand. Protective footwear is effective in reducing infection. Thiabendazole is an efficacious treatment.

Adult↗

PubMed2000

Obesity: a disease or a biological adaptation?

The increase in obesity prevalence is problematic as this condition is associated with health complications such as diabetes and cardiovascular diseases, more particularly when the excess body fat is stored in the deep abdominal region. On the other hand, obesity facilitates the maintenance of body homeostasis probably because of an increased hormonal gradient which favours the regulation of energy balance, to give but one example. The regulation potential of excess body fat is particularly apparent in the reduced-obese state where a reduction of energy expenditure, fat oxidation and some immune system markers, as well as an increase in appetite, stress vulnerability and circulating and adipose tissue organochlorines have been observed. These constitute another category of risk factors which can certainly favour the accumulation of body fat to reestablish body homeostasis on other fronts. Under such conditions, obesity is perceived by the physiologist as a necessary biological adaptation rather than a disease. For health professionals, this emphasizes the importance to seek a reasonable compromise between the favourable reduction of risk to develop metabolic complications by body weight loss and the physiological vulnerability which is also generated by such an intervention.

Adaptation, Physiological↗

PubMed2000

The association between vigorous physical activities and fat deposition in male adolescents.

PURPOSE: The aim of this study was to investigate the association between participation in vigorous physical activities (VPA) and indicators of adiposity and fat distribution in male adolescents. METHODS: Subjects were classified on the basis of the number of reported 15-min periods over 3 d during which VPA were performed. RESULTS: Body weight, fat mass, body mass index, sum of six subcutaneous skinfolds, trunk and extremity skinfolds, and trunk to extremity skinfolds ratio (T/E ratio) were all significantly and inversely related to a higher VPA participation. Moreover, T/E ratio was significantly lower in the subgroup reporting a mean of 7.8 15-min periods of activity for 3 d (equivalent to a mean of 39 min x d(-1)) compared with subjects reporting no participation. This decrease in T/E ratio was more pronounced in subjects reporting a mean of 13.6 15-min periods of VPA for 3 d. CONCLUSION: These observations reinforce the idea that excess abdominal fat accumulation can be prevented by regular participation in vigorous physical activities.

Abdomen↗

PubMed2000

A double-strand break in a chromosomal LINE element can be repaired by gene conversion with various endogenous LINE elements in mouse cells.

A double-strand break (DSB) in the mammalian genome has been shown to be a very potent signal for the cell to activate repair processes. Two different types of repair have been identified in mammalian cells. Broken ends can be rejoined with or without loss or addition of DNA or, alternatively, a homologous template can be used to repair the break. For most genomic sequences the latter event would involve allelic sequences present on the sister chromatid or homologous chromosome. However, since more than 30% of our genome consists of repetitive sequences, these would have the option of using nonallelic sequences for homologous repair. This could have an impact on the evolution of these sequences and of the genome itself. We have designed an assay to look at the repair of DSBs in LINE-1 (L1) elements which number 10(5) copies distributed throughout the genome of all mammals. We introduced into the genome of mouse epithelial cells an L1 element with an I-SceI endonuclease site. We induced DSBs at the I-SceI site and determined their mechanism of repair. We found that in over 95% of cases, the DSBs were repaired by an end-joining process. However, in almost 1% of cases, we found strong evidence for repair involving gene conversion with various endogenous L1 elements, with some being used preferentially. In particular, the T(F) family and the L1Md-A2 subfamily, which are the most active in retrotransposition, appeared to be contributing the most in this process. The degree of homology did not seem to be a determining factor in the selection of the endogenous elements used for repair but may be based instead on accessibility. Considering their abundance and dispersion, gene conversion between repetitive elements may be occurring frequently enough to be playing a role in their evolution.

Animals↗