Genetic Variation in Y-Chromosome Genes of Sika Deer (Cervus nippon) in Japan.

Sika deer (Cervus nippon) in Japan are classified into southern and northern groups. However, previous studies primarily relied on maternally inherited mitochondrial DNA (mtDNA). The paternally inherited Y-chromosome is useful for analyzing the contribution of males to the population genetic history of sika deer. In total, approximately 16 kb of partial sequences of four Y-chromosomal genes, Y-linked, sex-determining region Y, DEAD-box helicase 3 Y-linked, and Zinc finger protein Y-linked, were sequenced to investigate intraspecific variation. As a result, we identified nine intronic single nucleotide polymorphisms (SNPs) in 478 sika deer samples collected over the entire Japanese archipelago from Hokkaido to Kyushu. SNP genotyping revealed 10 distinct haplotypes (SYH1-SYH10). The most common haplotype (SYH1) was present in all populations and was the most abundant haplotype, identified in 80.3% of the sampled individuals. The remaining haplotypes were unique to a single locality. SYH1 was also central to all other haplotypes that diverged by a SNP, resulting in this haplotype being the core of a star-like cluster topography. We found that contrary to mtDNA patterns, there was no clear differentiation of Y-chromosome markers between the southern and the northern populations. Due to the female philopatry of sika deer, mtDNA may provide a highly structured differentiation of populations. On the other hand, the male-biased gene flow may provide a reduced differentiation of populations. Our findings revealed that the genetic structure of the Japanese sika deer is more complex than previously thought based on mtDNA-based phylogeographic studies.

Comparative morphology of the lingual papillae and their connective tissue cores in the tongue of the American mink, Neovison vison.

We observed the morphology of the lingual papillae (filiform, conical, fungiform, and vallate papillae, and lateral organ) and their connective tissue cores (CTCs) in the American mink (Neovison vison) using light and scanning electron microscopy. Filiform papillae were distributed on the apex linguae and rostral regions of the corpus linguae. Conical papillae were distributed over the caudal region and absent in the radix linguae. Numerous ridges were present in the radix linguae. Four to six vallate papillae were situated at the border between the corpus and radix linguae. Instead of foliate papillae, a pair of lateral organs was situated on the caudal edge of the corpus. The epithelial surface of each filiform papilla consisted of a single main process and 10-12 accessory processes. Notably, filiform papillae in the apex linguae exhibited morphological variation, and some were dome-like and lacked processes. In contrast, filiform papillae on the rostral part were not variable, were extended to a sharp tip, were associated with an eosinophilic stratum corneum, and lacked nuclei. The CTCs of the filiform papillae consisted of a main core and slender accessory cores surrounding a concavity. Those in the apex linguae were similar in appearance and consisted of main and adjacent accessory cores. The fungiform papillae had a dome-like epithelial surface and their CTCs were columnar, with upper concavities and flanges. The simplified lingual morphology of the American mink, particularly in the filiform papillae in the apex linguae, may be influenced by its diet and semiaquatic lifestyle.

Occurrence patterns of crop-foraging sika deer distribution in an agriculture-forest landscape revealed by nitrogen stable isotopes.

Conflicts arising from the consumption of anthropogenic foods by wildlife are increasing worldwide. Conventional tools for evaluating the spatial distribution pattern of large terrestrial mammals that consume anthropogenic foods have various limitations, despite their importance in management to mitigate conflicts. In this study, we examined the spatial distribution pattern of crop-foraging sika deer by performing nitrogen stable isotope analyses of bone collagen. We evaluated whether crop-foraging deer lived closer to agricultural crop fields during the winter and spring, when crop production decreases. We found that female deer in proximity to agricultural crop fields during the winter and spring were more likely to be crop-foraging individuals. Furthermore, the likelihood of crop consumption by females decreased by half as the distance to agricultural crop fields increased to 5-10 km. We did not detect a significant trend in the spatial distribution of crop-foraging male deer. The findings of spatial distribution patterns of crop-foraging female deer will be useful for the establishment of management areas, such as zonation, for efficient removal of them.