The Correspondence of Charles Darwin

Darwin, Charles

doi:10.1017/9781108662895

Cited by 6 publications

(6 citation statements)

References 136 publications

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“…However, the homothallic V. africanus is able to produces zygotes by self-fertilization between eggs and sperm within the same bisexual spheroid (Fig. 1), which may provide reproductive assurance when population density is low, as seen in flowering plants (1,2,37). Furthermore, V. africanus also performs "outcrossing" between eggs of a bisexual spheroid and sperm from the separate male spheroid in order to avoid inbreeding depression.…”

Section: Discussionmentioning

confidence: 99%

“…A s first noted by Darwin when studying plant sexuality, selffertilization can lead to inbreeding depression, though this potential disadvantage relative to outcrossing can be offset by higher probability of fertilization success (1,2). Thus, transitions between inbreeding and outbreeding mating systems attract the attention of evolutionary biologists and have been documented in sexual systems across a broad range of taxa including animals, land plants, algae (Fig.…”

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confidence: 99%

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Three genomes in the algal genus Volvox reveal the fate of a haploid sex-determining region after a transition to homothallism

Yamamoto

Hamaji

Kawai-Toyooka

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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Transitions between separate sexes (dioecy) and other mating systems are common across eukaryotes. Here, we study a change in a haploid dioecious green algal species with male- and female-determining chromosomes (U and V). The genus Volvox is an oogamous (with large, immotile female gametes and small, motile male gametes) and includes both heterothallic species (with distinct male and female genotypes, associated with a mating-type system that prevents fusion of gametes of the same sex) and homothallic species (bisexual, with the ability to self-fertilize). We date the origin of an expanded sex-determining region (SDR) in Volvox to at least 75 Mya, suggesting that homothallism represents a breakdown of dioecy (heterothallism). We investigated the involvement of the SDR of the U and V chromosomes in this transition. Using de novo whole-genome sequences, we identified a heteromorphic SDR of ca 1 Mbp in male and female genotypes of the heterothallic species Volvox reticuliferus and a homologous region (SDLR) in the closely related homothallic species Volvox africanus, which retained several different hallmark features of an SDR. The V. africanus SDLR includes a large region resembling the female SDR of the presumptive heterothallic ancestor, whereas most genes from the male SDR are absent. However, we found a multicopy array of the male-determining gene, MID, in a different genomic location from the SDLR. Thus, in V. africanus, an ancestrally female genotype may have acquired MID and thereby gained male traits.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Three genomes in the algal genus Volvox reveal the fate of a haploid sex-determining region after a transition to homothallism

Yamamoto

Hamaji

Kawai-Toyooka

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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“…When Joseph Hooker described Welwitschia for the first time, placing it in the Gnetaceae, he stated: "it is easy to suppose that we have in Welwitschia a transition in function, as well as in structure, between the gymnospermous and angiospermous Dicotyledons" (Hooker, 1863, p. 24). Darwin described this in a personal letter to Hooker as "a most grand case to connect two such groups" (Darwin, 1997).…”

Section: Plant Phylogeny In Darwin's Lifetimementioning

confidence: 99%

The origin of Darwin’s “abominable mystery”

Buggs

2021

American J of Botany

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The much-repeated term "Darwin's abominable mystery" is derived from a private letter written in 1879 by Charles Darwin to his friend Joseph Hooker, Director of the Royal Botanic Gardens Kew. In his letter, Darwin stated: "the rapid development as far as we can judge of all the higher plants within recent geological times is an abominable mystery" (Darwin, 2019, pp. 336-337). When the letter was first published in 1903, the volume's editors Francis Darwin and Albert Seward placed it under a page header "Evolution of Angiosperms" (Darwin and Seward, 1903, p. 21). "Darwin's abominable mystery" has ever since been a commonly used appellation in the scientific literature for a range of unanswered questions about the origin and diversification of this group (

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“…Charles Darwin used the term "recent" to refer to alluvial deposits that contained fossils of both existing and extinct species, although he objected to designating any epoch after humans. 19 Horner told his colleagues to start addressing the uncertainty clouding all time periods, including the most recent. He argued that geologists should now seek to "define a certain division of time in the history of the whole earth."…”

Section: Geological Chronology and The Missing Linkmentioning

confidence: 99%

Ancient Egypt and the geological antiquity of man, 1847–1863

Gold

2018

Hist Sci

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The 1850s through early 60s was a transformative period for nascent studies of the remote human past in Britain, across many disciplines. Naturalists and scholars with Egyptological knowledge fashioned themselves as authorities to contend with this divisive topic. In a characteristic case of long-distance fieldwork, British geologist Leonard Horner employed Turkish-born, English-educated, Cairo-based engineer Joseph Hekekyan to measure Nile silt deposits around pharaonic monuments in Egypt to address the chronological gap between the earliest historical and latest geological time. Their conclusion in 1858 that humans had existed in Egypt for exactly 13,371 years was the earliest attempt to apply geological stratigraphy to absolute human dates. The geochronology was particularly threatening to biblical orthodoxy, and the work raised private and public concerns about chronological expertise and methodology, scriptural and scientific authority, and the credibility of Egyptian informants. This essay traces these geo-archaeological investigations; including the movement of paper records, Hekekyan’s role as a go-between, and the publication’s reception in Britain. The diverse reactions to the Egyptian research reveal competing ways of knowing the prehistoric past and highlights mid-Victorian attempts to reshape the porous boundaries between scholarly studies of human antiquity.

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The Correspondence of Charles Darwin

Cited by 6 publications

References 136 publications

Three genomes in the algal genus Volvox reveal the fate of a haploid sex-determining region after a transition to homothallism

Three genomes in the algal genus Volvox reveal the fate of a haploid sex-determining region after a transition to homothallism

The origin of Darwin’s “abominable mystery”

Ancient Egypt and the geological antiquity of man, 1847–1863

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