Publications by authors named "Michael McGowen"

The dolphin genus Lagenorhynchus has included six species of dolphins characterized by short, wide rostra. Genetic analyses have consistently found the genus to be polyphyletic with four of the species being included in the subfamily Lissodelphininae. A recent paper synthesized available molecular, morphological and acoustic evidence to support a taxonomic revision of the genus, assigning L.

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Cetaceans have evolved unique limb structures, such as flippers, due to genetic changes during their transition to aquatic life. However, the full understanding of the genetic and evolutionary mechanisms behind these changes is still developing. By examining 25 limb-related protein-coding genes across various mammalian species, we compared genetic changes between aquatic mammals, like whales, and other mammals with unique limb structures such as bats, rodents and elephants.

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  • Toothed whales (Odontoceti) display a range of tooth and enamel types linked to their feeding habits, from complete teeth in dolphins to enamel-less teeth in some beaked whales.
  • Previous research found mutations in genes responsible for enamel production in odontocetes, but the relationship between enamel complexity and genetic selection pressure remains unclear.
  • This study analyzed enamel-specific gene sequences in 62 odontocete species, revealing fewer inactivating mutations in species with complex enamel, while those with simpler enamel exhibited higher mutation rates.
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  • Toothed whales use echolocation, emitting high-frequency sounds to detect prey and navigate their environment, enabled by their specialized jaw structure.
  • Research reveals significant evolutionary changes in the shape of the mandible over 50 million years, particularly during two main periods of rapid evolution related to dietary adaptations and the refinement of echolocation abilities.
  • Overall mandible shape is influenced by factors like diet and feeding methods, but remains relatively conservative in certain areas despite the evolution of sophisticated echolocation in these species.
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The large interspecific variation in marine mammal skull and dental morphology reflects ecological specialisations to foraging and communication. At the intraspecific level, the drivers of skull shape variation are less well understood, having implications for identifying putative local foraging adaptations and delineating populations and subspecies for taxonomy, systematics, management and conservation. Here, we assess the range-wide intraspecific variation in 71 grey seal skulls by 3D surface scanning, collection of cranial landmarks and geometric morphometric analysis.

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The deep sea has been described as the last major ecological frontier, as much of its biodiversity is yet to be discovered and described. Beaked whales (ziphiids) are among the most visible inhabitants of the deep sea, due to their large size and worldwide distribution, and their taxonomic diversity and much about their natural history remain poorly understood. We combine genomic and morphometric analyses to reveal a new Southern Hemisphere ziphiid species, Ramari's beaked whale, , whose name is linked to the Indigenous peoples of the lands from which the species holotype and paratypes were recovered.

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  • The transition from land to water in mammals has happened two times: in whales (Cetacea) and sea cows (Sirenia).
  • Research shows that whales and hippos are closely related, but adaptations to aquatic life likely developed separately in each group.
  • A study of skin-related genes reveals that specific changes for living in water occurred significantly earlier in whales compared to hippos, supporting the idea of independent evolutionary paths.
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  • The family Pteropodidae, consisting of over 200 species of Old World fruit bats, primarily feeds on fruit but some have shifted to nectar-based diets.
  • Over 50% of these species are threatened, and their evolutionary relationships have been complicated by ancient rapid diversification.
  • By analyzing the genetic data of 114 species, researchers have clarified the systematics of these bats, discovering at least seven dietary transitions and proposing a new genus based on their findings.
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The Atlantic humpback dolphin remains an understudied, critically endangered cetacean species. Here, we describe the first complete mitogenome of , derived from an animal stranded on Île des Oiseaux, Sine Saloum, Senegal. The mitogenome is composed of 16,384 base pairs and is 98.

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The Indo-Pacific humpback dolphin () is a small inshore species of odontocete cetacean listed as Vulnerable on the IUCN Red List. Here, we report on the evolution of . chromosomes from its cetruminant ancestor and elucidate the evolutionary history and population genetics of two neighboring .

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The diversity of the dolphin family was established during a short window of time. We investigated delphinid skull shape evolution, mapping shapes on an up-to-date nuclear phylogeny. In this model, the common ancestor was similar to .

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The transition to an aquatic lifestyle in cetaceans (whales and dolphins) resulted in a radical transformation in their sensory systems. Toothed whales acquired specialized high-frequency hearing tied to the evolution of echolocation, whereas baleen whales evolved low-frequency hearing. More generally, all cetaceans show adaptations for hearing and seeing underwater.

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Phylogeographic inference has provided extensive insight into the relative roles of geographical isolation and ecological processes during evolutionary radiations. However, the importance of cross-lineage admixture in facilitating adaptive radiations is increasingly being recognised, and suggested as a main cause of phylogenetic uncertainty. In this study, we used a double digest RADseq protocol to provide a high resolution (~4 Million bp) nuclear phylogeny of the Delphininae.

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The evolution of cetaceans, from their early transition to an aquatic lifestyle to their subsequent diversification, has been the subject of numerous studies. However, although the higher-level relationships among cetacean families have been largely settled, several aspects of the systematics within these groups remain unresolved. Problematic clades include the oceanic dolphins (37 spp.

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Anthropoid primates arose during the Eocene approximately 55 million years ago (mya), and extant anthropoids share a most recent common ancestor ∼40mya. Paleontology has been very successful at describing the morphological phenotypes of extinct anthropoids. Less well understood is the molecular biology of these extinct species as well as the phenotypic consequences of evolutionary variation in their genomes.

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Introduction: The placenta is arguably the most anatomically variable organ in mammals even though its primary function is conserved.

Method: Using RNA-Seq, we measured the expression profiles of 55 term placentas of 14 species of mammals representing all major eutherian superordinal clades and marsupials, and compared the evolution of expression across clades.

Results: We identified a set of 115 core genes which is expressed (FPKM ≥10) in all eutherian placentas, including genes with immune-modulating properties (ANXA2, ANXA1, S100A11, S100A10, and LGALS1), cell-cell interactions (LAMC1, LUM, and LGALS1), invasion (GRB2 and RALB) and syncytialization (ANXA5 and ANXA1).

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The dramatic increase in the application of genomic techniques to non-model organisms (NMOs) over the past decade has yielded numerous valuable contributions to evolutionary biology and ecology, many of which would not have been possible with traditional genetic markers. We review this recent progression with a particular focus on genomic studies of marine mammals, a group of taxa that represent key macroevolutionary transitions from terrestrial to marine environments and for which available genomic resources have recently undergone notable rapid growth. Genomic studies of NMOs utilize an expanding range of approaches, including whole genome sequencing, restriction site-associated DNA sequencing, array-based sequencing of single nucleotide polymorphisms and target sequence probes (e.

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  • Recent studies on cetaceans have mostly overlooked the hippopotamus, which limits understanding of when molecular adaptations occurred related to aquatic life.
  • The researchers analyzed new transcriptomes from both hippopotamus and humpback whale, as well as data from eight other cetaceans, creating the largest phylogenomic dataset for these animals with over 11,000 orthologous genes.
  • Findings revealed that most molecular adaptations in modern cetaceans emerged after their evolutionary split from hippopotamuses, with significant changes in genes related to lipid metabolism, hypoxia, and brain function.
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  • The research highlights significant differences in gene structure and transcription between humans and the western lowland gorilla, despite their close evolutionary relationship.
  • A study of the gorilla's brain transcriptome revealed unique genes that are absent in humans, especially in regions related to immunity and energy metabolism, accounting for 134 missing amino acids in proteins.
  • This work provides a valuable resource for understanding the genetic basis of cognitive differences between humans and other great apes by cataloging unique sequences and structures in the gorilla brain.
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Embryo implantation varies widely in placental mammals. We review this variation in mammals with a special focus on two features: the depth of implantation and embryonic diapause. We discuss the two major types of implantation depth, superficial and interstitial, and map this character on a well-resolved molecular phylogenetic tree of placental mammals.

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The blind mole rat (BMR), Spalax galili, is an excellent model for studying mammalian adaptation to life underground and medical applications. The BMR spends its entire life underground, protecting itself from predators and climatic fluctuations while challenging it with multiple stressors such as darkness, hypoxia, hypercapnia, energetics and high pathonecity. Here we sequence and analyse the BMR genome and transcriptome, highlighting the possible genomic adaptive responses to the underground stressors.

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Cetacea (whales, dolphins, and porpoises) is a model group for investigating the molecular signature of macroevolutionary transitions. Recent research has begun to reveal the molecular underpinnings of the remarkable anatomical and behavioral transformation in this clade. This shift from terrestrial to aquatic environments is arguably the best-understood major morphological transition in vertebrate evolution.

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