DOI: 10.3897/zoologia.38.e58607

Authors: Luye Shi, Mengwan Jiang, Mengyang Li, Xiaozhen Shang, Xiujuan Li, Maolin Huang, Yue Wu, Congcong Qiao, Xinrui Wang, Xiangyu Tian, Yuhua Shi, Zhenlong Wang

Abstract: The response mechanism and interaction patterns of HIF-1α and p53 in animals in an hypoxic environment are crucial for their hypoxic tolerance and adaptation. Many studies have shown that underground rodents have better hypoxic adaptation characteristics. However, the mechanism by which HIF-1α and p53 in underground rodents respond to hypoxic environments compared with in ground rodents remains unclear. Further, whether a synergy between HIF-1α and p53 enables animals tolerate extremely hypoxic environments is unclear. We studied HIF-1α and p53 expression in the brain tissue and cell apoptosis in the hippocampal CA1 region during 6 hours of acute hypoxia (5% oxygen) in Lasiopodomys mandarinus (Milne-Edwards, 1871) and Lasiopodomys brandtii (Radde, 1861), two closely related small rodents with different life characteristics (underground and aboveground, respectively), using a comparative biology method to determine the mechanisms underlying their adaptation to this environment. Our results indicate that HIF-1α and p53 expression is more rapid in L. mandarinus than in L. brandtii under acute hypoxic environments, resulting in a significant synergistic effect in L. mandarinus. Correlation analysis revealed that HIF-1α expression and the apoptotic index of the hippocampal CA1 regions of the brain tissues of L. mandarinus and L. brandtii, both under hypoxia, were significantly negatively and positively correlated, respectively. Long-term existence in underground burrow systems could enable better adaptation to hypoxia in L. mandarinus than in L. brandtii. We speculate that L. mandarinus can quickly eliminate resulting damage via the synergistic effect of p53 and HIF-1α in response to acute hypoxic environments, helping the organism quickly return to a normal state after the stress.

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DOI: 10.3897/zoologia.37.e49046

Authors: Jie Gong, Baohua Chen, Bijun Li, Zhixiong Zhou, Yue Shi, Qiaozhen Ke, Dianchang Zhang, Peng Xu

Abstract: The whole mitochondrial genome of Lateolabrax maculatus (Cuvier, 1828) was used to investigate the reasons for the observed patterns of genetic differentiation among 12 populations in northern and southern China. The haplotype diversity and nucleotide diversity of L. maculatus were 0.998 and 0.00169, respectively. Pairwise FST values between populations ranged from 0.001 to 0.429, correlating positively with geographic distance. Genetic structure analysis and haplotype network analysis indicated that these populations were split into two groups, in agreement with geographic segregation and environment. Tajima’s D values, Fu’s Fs tests and Bayesian skyline plot (BSP) indicated that a demographic expansion event may have occurred in the history of L. maculatus. Through selection pressure analysis, we found evidence of significant negative selection at the ATP6, ND3, Cytb, COX3, COX2 and COX1 genes. In our hypotheses, this study implied that demographic events and selection of local environmental conditions, including temperature, are responsible for population divergence. These findings are a step forward toward the understanding of the genetic basis of differentiation and adaptation, as well as conservation of L. maculatus.

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DOI: 10.3897/zoologia.36.e32771

Authors: Reinaldo T. Medeiros, Flávia G. Chaves, Maurício B. Vecchi, Denise M. Nogueira, Maria Alice S. Alves

Abstract: Variation in the morphometry of individuals in a population may result from natural or sexual selection. In the present study we investigated morphometric differences between males and females of a bird species endemic to the Brazilian Atlantic Forest, the Hangnest Tody-Tyrant, Hemitriccus nidipendulus (Wied, 1831), with no apparent sexual dimorphism. All individuals (n = 56) were sexed by PCR amplification of the intronic fragments of the CHDZ/CHDW alleles obtained from blood samples, and 12 morphometric measurements were recorded. The molecular configuration was similar to that described for other species of Passeriformes, with males presenting a single band of approximately 360 base pairs (bp), and females with two bands of 360 and 400 bp. Males had significantly larger tarsi and wings than the females, while the females had two larger beak measurements. This indicates that differential selection pressures may be modeling the morphometry of the Hangnest Tody-Tyrant. In the males, larger tarsi and wings may be beneficial for the exploration of the habitat or the acquisition of potential mates, while females with larger beaks may be able to exploit larger food items and forage more efficiently. However, these hypotheses need to be tested empirically in future studies.

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