Phylogeny of Normal and Abnormal Hemoglobin Genes
S. K. Dutta in DNA Systematics, 2019
The second developmental feature which is striking is that the genes are arranged on the chromosome in order of expression. This is true not only for man but also for the rabbit, the mouse, various primates, sheep, and goats4,20,22 and may therefore be a widespread and perhaps universal characteristic. The significance of this observation remains something of a mystery. One of the hoary maxims of classical descriptive biology is that “ontogeny recapitulates phylogeny” — a reference to the at least superficial resemblance between various developmental stages and the lower forms which preceded man on the evolutionary scale. Whether this observed parallel between position and development carries any as yet undeciphered message of phylogenetic importance remains to be seen.
Anatomy and Embryology of the External and Middle Ear
John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed in Paediatrics, The Ear, Skull Base, 2018
During growth from the fertilized egg into the fully formed foetus, animals pass through phases that represent, to a certain degree at least, their evolutionary precursors. The phrase ‘ontogeny recapitulates phylogeny’ has been used to express this reflection of earlier forms. In mammals, a phase is reached during early embryonic life when the mesenchyme surrounding the primitive foregut and pharynx differentiates into a maxillary and mandibular swelling on each side of the midline just above and below the buccopharyngeal membrane. This membrane then breaks down and a space, which will later become both nasal and buccal cavities, is formed. Further down the embryo and in the mesenchyme surrounding the pharynx, five or six parallel thickenings develop as bands that surround the pharynx. These are the branchial arches, which are numbered 1 to 5 from head to tail. They are formed anterior to the 40–43 paired somites that subsequently give rise to the trunk and limbs. On the external surface a groove develops between each branchial arch and this is matched by a cleft or pouch on the inner pharyngeal surface. In each branchial arch a bar of cartilage, a group of muscles, an associated artery and a cranial nerve, supplying these structures and their derivatives, all develop. The cranial nerve is called the post-trematic nerve. In addition, a nerve from the arch lower down supplies the inner endodermal surface of the arch above and is called the pretrematic nerve.
Cancer
Shamim I. Ahmad in Aging: Exploring a Complex Phenomenon, 2017
Developmental biology traditionally presents the human ontogeny with emphasis on the birth of a child or on body growth. However, aging is another integral component of human ontogeny. This process seems to be influenced by many endogenous as well as exogenous factors. It was described in monozygotic twins that the age of onset, as well as disease occurrence and course, can be quite discordant [67,68]. However, our life span seems to be genetically determined including reduced activity of gene repair that can reflect the high incidence of malignant tumors in the elderly. The activity of genes such as transcription factors of the FOXO family can affect the extreme longevity of centenarians in a pleiotropic manner, influencing several cell-regulated activities such as stress resistance, metabolism, cell cycle arrest, and apoptosis, and probably minimize cancer incidence in the elderly [69].
The use of in silico extreme pathway (ExPa) analysis to identify conserved reproductive transcriptional-regulatory networks in humans, mice, and zebrafish
Published in Systems Biology in Reproductive Medicine, 2023
David Hala
Overall, ExPa analyses indicated a considerable conservation of reproductive TRNs between mammals and zebrafish. Factor analysis across all aggregated life-stages also supported this observation (Figure 5). Given the reliance of zebrafish sex differentiation on germ cell numbers established during the bipotential stage (Kossack and Draper 2019), the conserved reproductive TRNs between zebrafish and mammals were mostly for the maintenance of sexual differentiation (once it is established). As a result, regardless of a lack of sex determination genes in zebrafish the TRNs responsible for canalizing male vs. female sexual differentiation were conserved with mammalian taxa. The discrete dynamics of gene activations over ontogeny precludes the predominance of hierarchical ‘master’ regulators. In so much is evident whereby knock-outs or mutations of either sex determination or differentiation genes result in sex reversal or reproductive functional dysgenesis (Ono and Harley 2013; Ohnesorg et al. 2014). Therefore evolutionarily, control appears distributed with ‘parliamentary’ decision-making resting with ensembles of genes active at particular developmental stages (albeit their activations being dependent upon those of preceding genes) (Capel 2017). Finally, limitations of the in silico and in vivo model systems are considered below.
Influencing tumor-associated macrophages in malignant melanoma with monoclonal antibodies
Published in OncoImmunology, 2022
Rebecca Adams, Gabriel Osborn, Bipashna Mukhia, Roman Laddach, Zena Willsmore, Alicia Chenoweth, Jenny L C Geh, Alastair D MacKenzie Ross, Ciaran Healy, Linda Barber, Sophia Tsoka, Victoria Sanz-Moreno, Katie E Lacy, Sophia N Karagiannis
Melanoma-associated macrophages can derive either from embryonic-derived tissue resident macrophages (Res-TAMs), recruited and maintained by colony-stimulating factor-1 (CSF-1) binding its receptor CSF1R,25 or through the recruitment of circulating monocytes via the CCL2/CCR2 chemokine pathway, which can differentiate into monocyte-derived macrophages (mo-TAMs).26–28 The exact contributions of each origin pool are still being explored, with a paucity of information on how macrophage ontogeny affects TAM function within melanoma. Much knowledge of ontogeny derives from mouse studies, due to the inability to undertake fate-mapping studies in humans. Alongside this, genetic similarities and a lack of markers that can help distinguish tissue-resident from monocyte-derived macrophages render further exploration into this area quite challenging.29 It appears that tissue resident macrophages are the first to be influenced by factors secreted from tumors. However, in the cancer types studied so far, the contribution of Res-TAMs and mo-TAMs appears organ specific:29–31 in pancreatic cancer models, Res-TAMs appeared to promote tumor growth; in human glioma samples mo-TAMs correlate with tumor grade; and in mouse models of lung cancer, macrophages of both origins appear to contribute to tumor growth. No such comparative studies of how macrophage origin can affect function have been carried out in melanoma.
The foraging gene as a modulator of division of labour in social insects
Published in Journal of Neurogenetics, 2021
Christophe Lucas, Yehuda Ben-Shahar
Over 50years ago, the pioneering ethologist Niko Tinbergen published his seminal paper entitled “On aims and methods of ethology” (Burkhardt, 2014; Tinbergen, 1963). With brilliant simplicity, Tinbergen argued that if biologists want to really understand “behaviour” then they need to ask the following four questions (rephrased): (1) What is the studied trait good for (its impact on fitness)? (2) How does it develop during the lifetime of an individual (development/ontogeny)? (3) How did it evolve over the history of the species (trait phylogeny)? (4) How does it work (mechanism/causation)? The emergence of modern neuroscience and neurogenetics followed in the footsteps of ethology by providing a mechanistic framework as a powerful approach to the design of behavioural studies and their interpretation in the context of brain functions (Tinbergen question #4).
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