Pleistocene
The Pleistocene was the Ice Age period of Earth’s history extending from roughly 2.6 million years ago to 11,700 years ago defined by recurring cycles of glaciers expanding and melting. According to the scientists the whales endured a long-term decline followed by dramatic declines during the Ice Age most likely due to moving glaciers and climate changes that impacted their habitat and food sources.
autosome-wide heterozygosity was 0.00102, which is higher than that of most mammals for which comparable estimates are calculated using the same parameters, and three times higher than a conspecific individual from the Eastern-Canada-West-Greenland bowhead whale stock
Shows that bowhead whales have a greater heterozygosity value 0.00102 compared to other animals, including cetaceans. Despite the population's endangered status this demonstrates surprisingly high genetic diversity.Figure4
No obvious population structuring was identified.
This explains Figure 2 in which all 12 whales are densely clustered with no separate groupings. The PCA points do not form discrete clusters indicating that all of the whales are from the same genetically homogeneous stock.
cetacean
Whales, dolphins, porpoises, and other totally aquatic mammals are classified as cetaceans. Whales and dolphins are examples of cetaceans which are marine mammals that breathe air through blowholes and live fully in the water.
Genetic sex deter- its degree of degradation (Figure 1) and, thus, inmined by our new method was consistent with the its ratio of amplifiable DNA to total DNA. This,field data. Further demonstrating the reliability of in turn, impacts the success of amplification. Wethis method, a male used as a control was sexed 15 have found that this sexing method can reliablytimes, and 17 other individuals were sexed twice, be used to determine the relative amplifiability ofproviding consistent results each time. degraded DNA, which then allows the success ofFor low-quality sperm whale samples
This validates the accuracy and repeatability of the new 94-bp PCR method. The authors tested multiple samples repeatedly and obtained identical results confirming that the technique produces consistent outcomes even with degraded DNA. This builds confidence in using the assay for real-world cetacean studies.
All samples1x PCR buffer, with 0.4 mg/mL bovine serum albu- were used as templates in reactions with Rosel’smin (BSA), 1.5 mM MgCl2, 0.2 mM of each dNTP, primers and with CetSex94-F and CetSex94-R
Only the primers part I’m having a hard time selecting specific annotation . This demonstrates the researchers' primary experimental strategy they developed novel primers that amplify a 94 bp DNA fragment enabling the analysis of even damaged cetacean DNA. This is important since pieces larger than 300 bp caused the majority of previous PCR based sexing techniques to fail.
Determining the sex of individuals in wild popu- Currently, only one molecular sexing method forlations is important to many areas of study from cetaceans addresses the issues of fragment lengthsocial structure and behavioral studies to popula- and multiplexed primer sets. Morin et al. (2005)tion genetics.
Only first sentence…… When physical traits cannot accurately determine a cetacean's sex the authors describe molecular sexing as a genetic technique. This identifies the aim of the work, which is to increase the precision of sex determination from damaged DNA particularly in species that do not exhibit obvious sexual dimorphism.
Dam constructions threaten aquatic fauna, degrading their habitats and causing population fragmentation.
This reveals that the broader threat populations which was caused by the construction
Dolphins were actively searched along linear transects in four sections of the river: Abunã, Mutum, Caiçara and Canteiro, over 125 km (250 km round trip).
This reveals the monitoring of the areas which they did the study...linear transects
A total effort of 986 h was carried out along 210 days during the hydrological seasons (falling, low, rising and high-water level). Twenty-nine (29) groups were recorded BRF in the direct dam influence area (N = 62), while thirty-eight (38) groups were documented ARF (N = 111). The highest number of sightings was recorded in Abunã during both periods: 24 in BRF (N = 50) and 33 in ARF (N = 101). The greatest number of dolphins was detected during the falling and low hydrological seasons: 19 in BRF (N = 48) and 30 in ARF (N = 92)
This shows the survey effort which goes into how many hours and days it took for this process to complete and also reveals how the dolphins were monitored