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The Domestication of Humans
The domestication of humans is not an issue of domesticity but of the effects of the domestication syndrome on a hominin species and its genome. These effects are well expressed in the ‘anatomically modern humans’, in their physiology, behavior, genetic defects, neuropathology, and distinctive neoteny. The physiological differences between modern (gracile) humans and their ancestors, robust Homo sapiens types, are all accounted for by the domestication syndrome. From deductions we can draw about early human behavior, it appears that modifications are attributable to the same cause. The domestication hypothesis ascribes the initiation of the changes to selective breeding introduced by the consistent selection of neotenous features. That would trigger genetic pleiotropy, causing the changes that are observed.
  • 422
  • 31 Jul 2023
Topic Review
The Chromosome Organization in the Cell Nuclei
The spatial organization of the genome into the cell nucleus plays a central role in controlling several genome functions, such as gene expression and DNA replication timing during the S-phase of the cell cycle. Here we show how chromosomes are organized in the cell nucleus according to the gene density and to the GC-level of the various chromosomal bands, allowing a corrected and coordinated gene expression during cell life. The human genome, such as the genome of the other mammals, is composed by two very different parts: one very gene-dense, replicated at the onset of the S-phase, very GC-rich and the other endowed with opposite features. These two genomic compartments are localized far apart within a chromosome, with regions having intermediate properties located between them. This determines a zig-zag organization of the larger chromosomes, to position the gene-poorest genome compartment at the nuclear periphery and the gene-richest one at the nuclear interior.
  • 884
  • 05 Jan 2022
Topic Review
TH Signalling in Human Evolution
Thyroid hormone (TH) signalling is a universally conserved pathway with pleiotropic actions that is able to control the development, metabolism, and homeostasis of organisms. TH signalling has likely played a critical role in human evolution by facilitating the adaptive responses of early hominids to unprecedently challenging and continuously changing environments.
  • 362
  • 30 Dec 2021
Topic Review
Taming, Domestication and Exaptation
During evolution, several types of sequences pass through genomes. Along with mutations and internal genetic tinkering, they are a useful source of genetic variability for adaptation and evolution. Most of these sequences are acquired by horizontal transfers (HT), but some of them may come from the genomes themselves. If they are not lost or eliminated quickly, they can be tamed, domesticated, or even exapted.
  • 444
  • 06 Jan 2022
Topic Review
Sex Determination and Differentiation in Southern Swordtail Fishes
Southern swordtail fishes, which belong to the viviparous teleosts called Xiphophorus, are unique models for studies of evolution of sex chromosomes. Monofactorial sex-determining systems, with either the male or the female being the heterogametic sex, as well as sex determination involving more than two sex chromosomes, are found in swordtails and related species. Some swordtail species seem to have originated by crossing between two closely related species. Although the sword has disappeared in many Xiphophorus species during evolution, females of non-sworded species still prefer sworded males, demonstrating a discrepancy between natural and sexual selection. Natural sex change has not been documented sufficiently convincingly in swordtails, but, at least in some subspecies, two or more male phenotypes exist.
  • 211
  • 14 Aug 2023
Topic Review
Self-Incompatibility in Orchids
Self-incompatibility (SI) refers to the inability of hermaphroditic angiosperms to self-pollinate, which promotes outcrossing or hybridization. 
  • 753
  • 13 Dec 2021
Topic Review
Segmentation
Segmentation in biology is the division of some animal and plant body plans into a series of repetitive segments. This article focuses on the segmentation of animal body plans, specifically using the examples of the taxa Arthropoda, Chordata, and Annelida. These three groups form segments by using a "growth zone" to direct and define the segments. While all three have a generally segmented body plan and use a growth zone, they use different mechanisms for generating this patterning. Even within these groups, different organisms have different mechanisms for segmenting the body. Segmentation of the body plan is important for allowing free movement and development of certain body parts. It also allows for regeneration in specific individuals.
  • 5.8K
  • 29 Sep 2022
Topic Review
Seeking Sense in the Hox Gene Cluster
The Hox gene cluster, responsible for patterning of the head–tail axis, is an ancestral feature of all bilaterally symmetrical animals (the Bilateria) that remains intact in a wide range of species.
  • 876
  • 20 Dec 2022
Topic Review
Saltation
In biology, saltation (from la saltus 'leap, jump') is a sudden and large mutational change from one generation to the next, potentially causing single-step speciation. This was historically offered as an alternative to Darwinism. Some forms of mutationism were effectively saltationist, implying large discontinuous jumps. Speciation, such as by polyploidy in plants, can sometimes be achieved in a single and in evolutionary terms sudden step. Evidence exists for various forms of saltation in a variety of organisms.
  • 2.8K
  • 29 Sep 2022
Topic Review
Retrovirus-Derived RTL/SIRH Genes in Eutherian Developmental System
Eutherians have 11 retrotransposon Gag-like (RTL)/sushi-ichi retrotransposon homolog (SIRH) genes presumably derived from a certain retrovirus. Accumulating evidence indicates that the RTL/SIRH genes play a variety of roles in the mammalian developmental system, such as in the placenta, brain, and innate immune system, in a eutherian-specific manner. It has been shown that the functional role of Paternally Expressed 10 (PEG10) in placental formation is unique to the therian mammals, as are the eutherian-specific roles of PEG10 and PEG11/RTL1 in maintaining the fetal capillary network and the endocrine regulation of RTL7/SIRH7 (aka Leucine Zipper Down-Regulated in Cancer 1 (LDOCK1)) in the placenta. In the brain, PEG11/RTL1 is expressed in the corticospinal tract and hippocampal commissure, mammalian-specific structures, and in the corpus callosum, a eutherian-specific structure. Unexpectedly, at least three RTL/SIRH genes, RTL5/SIRH8, RTL6/SIRH3, and RTL9/SIRH10, play important roles in combating a variety of pathogens, namely viruses, bacteria, and fungi, respectively, suggesting that the innate immunity system of the brain in eutherians has been enhanced by the emergence of these new components. 
  • 162
  • 25 Oct 2023
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