The dynamics of genome size and GC contents evolution in genus Nicotiana

Hybridization and Polyploidization are most common of the phenomenon observed in plants, especially in the genus Nicotiana leading to the duplication of genome. Although genomic changes associated with these events has been studied at various levels but the genome size and GC content variation is less understood because of absence of sufficient genomic data. In this study the flow cytometry technique was used to uncover the genome size and GC contents of 46 Nicotiana species and we compared the genomic changes associated with the hybridization events along evolutionary time scale. The genome size among Nicotiana species varied between 3.28 pg and 11.88 pg whereas GC contents varied between 37.22% and 51.25%. The tetraploid species in genus Nicotiana including section Polydiclae, Repandae, Nicotiana, Rustica and Sauveolentes revealed both up and downsizing in their genome sizes when compared to the sum of genomes of their ancestral species. The genome sizes of three homoploid hybrids were found near their ancestral species. Loss of large genome sequence was observed in the evolutionary more aged species (>10 Myr) as compared to the recently evolved one’s (<0.2 Myr). The GC contents were found homogenous with a mean difference of 2.46% among the Nicotiana species. It is concluded that genome size change appeared in either direction whereas the GC contents were found more homogenous in genus Nicotiana.

The material difference in human cognition

Humans leverage material forms for unique cognitive purposes: We recruit and incorporate them into our cognitive system, exploit them to accumulate and distribute cognitive effort, and use them to recreate phenotypic change in new individuals and generations. These purposes are exemplified by writing, a relatively recent tool that has become highly adept at eliciting specific psychological and behavioral responses in its users, capability it achieved by changing in ways that facilitated, accumulated, and distributed incremental behavioral and psychological change between individuals and generations. Writing is described here as a self-organizing system whose design features reflect points of maximal usefulness that emerged under sustained collective use of the tool. Such self-organization may hold insights applicable to human cognitive evolution and tool use more generally. Accordingly, this article examines the emergence of the ability to leverage material forms for cognitive purposes, using the tool-using behaviors and lithic technologies of ancestral species and contemporary non-human primates as proxies for matters like collective use, generational sustainment, and the nonteleological emergence of design features.

Comparative mitogenome analyses uncover mitogenome features and phylogenetic implications of the subfamily Cobitinae

Background Loaches of Cobitinae, widely distributed in Eurasian continent, have high economic, ornamental and scientific value. However, the phylogeny of Cobitinae fishes within genera or family level remains complex and controversial. Up to now, about 60 Cobitinae mitogenomes had been deposited in GenBank, but their integrated characteristics were not elaborated. Results In this study, we sequenced and analyzed the complete mitogenomes of a female Cobits macrostigma. Then we conducted a comparative mitogenome analysis and revealed the conserved and unique characteristics of 58 Cobitinae mitogenomes, including C. macrostigma. Cobitinae mitogenomes display highly conserved tRNA secondary structure, overlaps and non-coding intergenic spacers. In addition, distinct base compositions were observed among different genus and significantly negative linear correlation between AT% and AT-skew were found among Cobitinae, genus Cobitis and Pangio mitogenomes, respectively. A specific 3 bp insertion (GCA) in the atp8-atp6 overlap was identified as a unique feature of loaches, compared to other Cypriniformes fish. Additionally, all protein coding genes underwent a strong purifying selection. Phylogenetic analysis strongly supported the paraphyly of Cobitis and polyphyly of Misgurnus. The strict molecular clock predicted that Cobitinae might have split into northern and southern lineages in the late Eocene (42.11 Ma), furthermore, mtDNA introgression might occur (14.40 Ma) between ancestral species of Cobitis and ancestral species of Misgurnus. Conclusions The current study represents the first comparative mitogenomic and phylogenetic analyses within Cobitinae and provides new insights into the mitogenome features and evolution of fishes belonging to the cobitinae family.

Identification of Bread and Durum Wheats from their Diploid Ancestral Species Based on Chloroplast DNA

Species that have been identified as the genome donors to cultivated polyploid durum and bread wheats (Triticum durum L. and T. aestivum L., respectively) are potential gene sources for the breeding of these two crops. Therefore, their accurate identification facilitates their use in the improvement of these crops. Based on chloroplast DNA analysis (rpL2 and rps16 introns, psbC-trnS, trnT-L, and trnL-F) using polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP), an attempt was made in 2018 (Department of Molecular Biology and Biotechnology/AECS) to identify durum and bread wheats from each of their proposed diploid ancestral species (i.e., T. monococcum, T. urartu, Aegilops speltoides, and Ae. tauschii). The use of two PCR markers (psbC-trnS and trnL-F) and three PCR-RFLP locus-enzyme combinations (rps16 intron-Tru 1I, rpL2 intron-Taq I, and trnT-L-Taq I) allowed the identification of all species involved. Reliable and accurate identification of diploid ancestors of durum and bread wheats using these candidate species-specific cpDNA markers will be useful for wheat breeding programs, in situ and ex situ conservation efforts, verification of seed purity in commercial seed stocks, and ensuring identity and integrity of accessions held within a collection does not change through unwanted gene flow or by genetic drift after regeneration by seed.

The material difference in human cognition

Humans leverage material forms for unique cognitive purposes: We recruit and incorporate them into our cognitive system, exploit them to accumulate and distribute cognitive effort, and use them to recreate phenotypic change in new individuals and generations. These purposes are exemplified by writing, a relatively recent tool that has become highly adept at eliciting specific psychological and behavioral responses in its users, capability it achieved by changing in ways that facilitated, accumulated, and distributed incremental behavioral and psychological change between individuals and generations. Writing is described here as a self-organizing system whose design features reflect points of maximal usefulness that emerged under sustained collective use of the tool. Such self-organization may hold insights applicable to human cognitive evolution and tool use more generally. Accordingly, this article examines the emergence of the ability to leverage material forms for cognitive purposes, using the tool-using behaviors and lithic technologies of ancestral species and contemporary non-human primates as proxies for matters like collective use, generational sustainment, and the non-teleological emergence of design features.

Phalangeal curvature in a chimpanzee raised like a human: Implications for inferring arboreality in fossil hominins

Arboreal primates such as chimpanzees exhibit pronounced curvature in their hand and foot phalanges, which is assumed to develop throughout life in response to mechanical loads produced by grasping and hanging from branches. Intriguingly, ancient fossil hominins also exhibit substantial phalangeal curvature, which, too, has been interpreted as a direct result of habitual arboreality during life. Here, we describe the phalangeal curvature of a chimpanzee who was raised during the 1930s in New York City to live much like a human, including by having very few opportunities to engage in arboreal activities. We show that the degree of hand and foot phalangeal curvature in this individual is indistinguishable from that of wild chimpanzees and distinct from humans. Thus, rather than being a direct effect of mechanical loads produced by lifetime arboreal activities, phalangeal curvature appears to be shaped largely by genetic factors. An important implication of this finding is that phalangeal curvature among fossil hominins is evidently best interpreted as a primitive trait inherited from an arboreal ancestral species rather than proof of engagement in arboreal activities during life.

The Pseudoomphalina kalchbrenneri complex in North America

Pseudoomphalina kalchbrenneri is a Eurasian species. In North America the Pso. kalchbrenneri complex is represented by Pseudoomphalina anticostica sp. nov. and Pso. compressipes in the east and Pso. intermedia in the west. Pseudoomphalina farinacea and Pso. felleoides are later synonyms for Pso. compressipes. The somewhat similar Pseudolaccaria pachyphylla occupies a temperate band through Eurasia, confirmed by sequencing in both eastern and western North America. It differs from species of the Pso. kalchbrenneri complex by smaller size, finely granular pileus, non-decurrent gills, and lack of hymenial cystidia. All species of the Pso. kalchbrenneri complex are uncommon, and macroscopically similar. Pseudoomphalina kalchbrenneri and Pso. intermedia can be identified by their distribution (Europe and western North America, respectively) and lack of cystidia. The cystidiate eastern North American Pso. anticostica and Pso. compressipes can be differentiated by the smaller spores of the latter. Pseudoomphalina cokeri is the most ancestral species on the Pseudoomphalina lineage, while Clitocybe thujana and Agaricus apertus (Clitocybe/Clitocybula aperta) fall outside Pseudoomphalina and Pseudolaccaria. We add 21 new sequences to GenBank, including six types (Agaricus compressipes, Clitocybe felleoides, C. farinacea, C. intermedia, C. thujana, Agaricus apertus), and one new species (Pso. anticostica).

The humble heredity of humongous hemispheres

In this chapter, a distant ancestor makes a success of greed, laziness, and fear; a driver hits the jackpot; and Dorothy comes to a fork in the yellow brick road. But mainly we consider how the brain evolved. A succession of forks in our evolutionary road produced new brain areas that are crucial for memory. Each of these areas has its own kind of memory, which evolved in a now-extinct ancestral species long ago. In each case, new forms of memory helped these species survive and thrive in circumstances very different from our own. During human evolution, the brain began expanding about 3 million years ago. It reached its current size and shape about 400,000 years ago, long before the acceleration in cultural innovation that characterizes human societies.

The Evolutionary Road to Human Memory

We tend to think about memory in terms of our own experience, but a series of our direct ancestors—from the earliest vertebrates to archaic humans—also had memories. The evolutionary history that we share with these ancestral species has left its mark on modern memory, complemented by other forms of memory that are uniquely human. This book traces the long evolutionary road to human memory by explaining how a series of now-extinct ancestral species adapted to life in their world, in their time and place. As they did, new brain areas appeared, each of which supported an innovative form of memory that helped them gain an advantage in life. Through inheritance and modification across millions of years, these evolutionary novelties created several kinds of memory that influence the human mind today. Then, during human evolution, yet another new kind of memory emerged: about ourselves and others. This evolutionary innovation ignited human imagination; empowered us to remember and talk about a personal past; and enabled the sharing of knowledge about our world, our cultures, and ourselves. Through these developments, evolution made it possible for every individual, day upon day, to add new pages to the story of a life: the remarkable, rich record of experiences and knowledge that make up a human mind.