Serial founder effects and genetic differentiation during worldwide range expansion of monarch butterflies.

Range expansions can result in founder effects, increasing genetic differentiation between expanding populations and reducing genetic diversity along the expansion front. However, few studies have addressed these effects in long-distance migratory species, for which high dispersal ability might counter the effects of genetic drift. Monarchs (Danaus plexippus) are best known for undertaking a long-distance annual migration in North America, but have also dispersed around the world to form populations that do not migrate or travel only short distances. Here, we used microsatellite markers to assess genetic differentiation among 18 monarch populations and to determine worldwide colonization routes. Our results indicate that North American monarch populations connected by land show limited differentiation, probably because of the monarch's ability to migrate long distances. Conversely, we found high genetic differentiation between populations separated by large bodies of water. Moreover, we show evidence for serial founder effects across the Pacific, suggesting stepwise dispersal from a North American origin. These findings demonstrate that genetic drift played a major role in shaping allele frequencies and created genetic differentiation among newly formed populations. Thus, range expansion can give rise to genetic differentiation and declines in genetic diversity, even in highly mobile species.

Association Between Hemoglobin A1c and Midurethral Sling Complications in Diabetic Women: A Cohort Study.

OBJECTIVE: We aimed to evaluate the association between hemoglobin A1c (HbA1c) levels and midurethral sling (MUS) complications. METHODS: This was a multihospital, retrospective cohort study from 2010 to 2020. We included all women with diabetes mellitus who underwent a synthetic mesh MUS procedure and had a preoperative HbA1c within 3 months of surgery. The primary outcome was a composite of complications, including MUS mesh exposure, surgical site granulation tissue or infection, urinary tract infection, surgical site pain beyond 6 weeks postoperatively, and MUS failure. A sensitivity analysis analyzing MUS failure alone was performed. RESULTS: During the study period, 109 women met the inclusion criteria. Most were White (52.2%) and had a median body mass index of 31.2 kg/m2, and 84.9% were postmenopausal. Median HbA1c was 7.2% (interquartile range, 6.3%-7.7%). Urinary tract infection was the most common complication in 12 (11.0%) women. Mesh exposure was diagnosed in 7 (6.4%) women. Seventeen (15.6%) had MUS failure. On univariate regression analysis, a higher HbA1c was associated with increased odds of composite complications (odds ratio, 1.67; 95% confidence interval, 1.20-2.32; P = 0.002) and MUS failure (odds ratio, 1.81, 95% confidence interval, 1.26-2.60; P = 0.001). On multivariate analysis, higher HbA1c levels were associated with a composite of complications and failure (P < 0.05). Based on the receiver operating characteristic curve, HbA1c greater than 8% demonstrated a specificity of 85.7% and a sensitivity of 50% for MUS failure. CONCLUSIONS: In diabetic patients, a higher HbA1c was associated with a higher risk of MUS complications and failure. Obtaining an HbA1c within 3 months of surgery may help with risk stratification.