Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant form of muscular dystrophy. The FSHD locus has been linked to the most distal genetic markers on the long arm of chromosome 4. Recently, a probe was identified that detects an EcoRI fragment length polymorphism which segregates with the disease in most FSHD families. Within the EcoRI fragment lies a tandem array of 3.2 kb repeats. In several familial cases and four independent sporadic FSHD mutations, the variation in size of the EcoRI fragment was due to a decrease in copy number of the 3.2 kb repeats. To gain further insight into the relationship between the tandem array and FSHD, a single 3.2 kb repeat unit was characterized. Fluorescence in situ hybridization (FISH) demonstrates that the 3.2 kb repeat cross-hybridizes to several regions of heterochromatin in the human genome. In addition, DNA sequence analysis of the repeat reveals a region which is highly homologous to a previously identified family of heterochromatic repeats, LSau. FISH on interphase chromosomes demonstrates that the tandem array of 3.2 kb repeats lies within 215 kb of the 4q telomere. Together, these results suggest that the tandem array of 3.2 kb repeats, tightly linked to the FSHD locus, is contained in heterochromatin adjacent to the telomere. In addition, they are consistent with the hypothesis that the gene responsible for FSHD may be subjected to position effect variegation because of its proximity to telomeric heterochromatin.

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Global climate change is increasing the frequency and severity of extreme climatic events (ECEs) which may be especially detrimental during late‐winter when many species are surviving on scarce resources. However, monitoring animal populations relative to ECEs is logistically challenging. Crowd‐sourced datasets may provide opportunity to monitor species' responses to short‐term chance phenomena such as ECEs. We used 14 years of eBird—a global citizen science initiative—to examine distribution changes for seven wintering waterfowl species across North America in response to recent extreme winter polar vortex disruptions. To validate inferences from eBird, we compared eBird distribution changes against locational data from 362 GPS‐tagged Mallards (Anas platyrhynchos) in the Mississippi Flyway. Distributional shifts between eBird and GPS‐tagged Mallards were similar following an ECE in February 2021. In general, the ECE affected continental waterfowl population distributions; however, responses were variable across species and flyways. Waterfowl distributions tended to stay near wintering latitudes or moved north at lesser distances compared with non‐ECE years, suggesting preparedness for spring migration was a stronger “pull” than extreme weather was a “push” pressure. Surprisingly, larger‐bodied waterfowl with grubbing foraging strategies (i.e., geese) delayed their northward range shift during ECE years, whereas smaller‐bodied ducks were less affected. Lastly, wetland obligate species shifted southward during ECE years. Collectively, these results suggest specialized foraging strategies likely related to resource limitations, but not body size, necessitate movement from extreme late‐winter weather in waterfowl. Our results demonstrate eBird's potential to monitor population‐level effects of weather events, especially severe ECEs. eBird and other crowd‐sourced datasets can be valuable to identify species which are adaptable or vulnerable to ECEs and thus, begin to inform conservation policy and management to combat negative effects of global climate change.

The Florida mottled duck (Anas fulvigula fulvigula) is threatened by introgression through hybridization with feral mallards (A. platyrhynchos). An essential component in managing this threat is the ability to accurately distinguish mottled ducks from mallards and hybrids in the wild. We provide a genetically cross‐validated phenotype key that accurately identifies mottled ducks. We collected data on structural and plumage traits from museum specimens of Florida, USA, mottled ducks and mallards to identify morphological traits useful in this process. We performed extensive comparisons and discriminant function analysis to identify traits informative in distinguishing the 2 species. We used these traits to preliminarily assign 168 contemporary birds as putative mottled duck, mallard, or hybrid. We collected tissue samples from each contemporary specimen and amplified and genotyped associated DNA. We used microsatellite markers to determine posterior probability species assignments for the 168 specimens. We then performed recursive partitioning of phenotypic traits and posterior genotype assignments to create identification keys based on the most informative traits separating mottled ducks from mallards and hybrids. Finally, we cross‐validated the keys by comparing assignments made using the key to those from genotyping for 339 wild ducks. The keys were >90% accurate, which suggests that their adoption will increase the ability of managers to address the threat of hybridization by mallards by allowing mottled ducks to be distinguished from other ducks in Florida. Our research provides a methodology to develop genetically cross‐validated identification keys for other species threatened by genetic introgression. © 2016 The Wildlife Society.