Preprint Review Version 3 Preserved in Portico This version is not peer-reviewed

Fan-shaped Spectrums of Species and Paleopolyploidy for Foundation of Crossbreeding Evolution

Version 1 : Received: 14 July 2020 / Approved: 15 July 2020 / Online: 15 July 2020 (09:23:24 CEST)
Version 2 : Received: 29 November 2021 / Approved: 30 November 2021 / Online: 30 November 2021 (11:04:43 CET)
Version 3 : Received: 2 March 2022 / Approved: 3 March 2022 / Online: 3 March 2022 (10:25:51 CET)

How to cite: Liu, L. Fan-shaped Spectrums of Species and Paleopolyploidy for Foundation of Crossbreeding Evolution. Preprints 2020, 2020070328 (doi: 10.20944/preprints202007.0328.v3). Liu, L. Fan-shaped Spectrums of Species and Paleopolyploidy for Foundation of Crossbreeding Evolution. Preprints 2020, 2020070328 (doi: 10.20944/preprints202007.0328.v3).


Although Darwin‘s evolutionary mutation theory has been widely accepted, many endeavors have been tried to challenge it. With more and more observation of successful hybridization and hybrids, the sexual isolation between species has become vague. The mechanism of evolution has been expanded from the classical model of evolution to multiple routes of speciation. Furthermore, a fundamental crossbreeding theory has been raised and proved by two lines of evidences: paleopolyploidy and fan-shaped spectrum of species. Ancient genome duplications are widespread throughout eukaryotic lineages, particularly in plants. The genome polyploidization, especially in the somatic cell hybridization, can break through the sexual incompatibility between diploid counterparts to hybridize and produce new species. By comparing characteristics, all species in every taxon, both in the extinct fossil and extant organisms, can be arranged into fan-shaped spectrum according to their similarity: left primitive type-middle advanced type-right primitive type. The species are primitive at the two ends and advanced at the middle. The primitive two species always resemble two types of more primitive species that can be confirmed as their ancestors respectively, and the middle species is half similar to the two ancestors respectively. These suggest that the species in the spectrum come from two different ancestors by crossbreeding and gene combination. As a sum, advanced species originated from crossbreeding of two primitive ancestors, by major method of polyploidization, and proved by results of fan-shaped spectrum of species. Then, sex is the cause, force and opportunity for evolution.


Evolution; Speciation; Crossbreeding; Hybridization; Species spectrum; Polyploidization; Somatic cell hybridization; Mutation



Comments (1)

Comment 1
Received: 3 March 2022
Commenter: Li-Yuan Liu
Commenter's Conflict of Interests: Author
Comment: 5. Somatic Cell HybridizationSomatic cell hybridization is a technique of fusion between different somatic cells from different tissues or species to produce hybrid cells in a cell culture. There is often one fused nucleus and the nuclear fusion can allow the recombination of chromosomal DNA for creating novel nuclear and/or cytoplasmic genomes, and produce a progeny with mixed characteristics. There are no hurdle of incompatibility (at interspecific, inter-generic or even at inter-kingdom levels) for the protoplast fusion (Sidebottom and Ringertz, 1984).Its major contribution to plant breeding is in overcoming common crossing barriers among plant species and in organelle genetics. The resulting hybrid has the chromosomes of both plants and it thus similar to polyploid plants. Protoplast fusion is a wonderful approach to overcome sexual incompatibility between different species of plants. Example-production of plant like pomato from potato and tomato (Sink et al 1992).In the animals, fusion of two different cells and production of a hybrid cell have been successfully achieved. It is interesting to note that the cells of taxonomically different animals can fuse and form hybrids. For instance, human-rodent somatic cell hybrids are developed by mixing human and mouse cells in the presence of the sendai virus. The hybrids contain the entire complement of the mouse genome and a few human chromosomes, because most human chromosomes are lost from the hybrid cell lines (Ohno-Shosaku et al 1984).The process of fusion can be achieved by spontaneous, mechanical, or induced fusion methods. As the spontaneous fusion, it is a natural process as is observed in case of egg fertilization. Actually, somatic hybridization is suitable for haploid protoplasts because fusion between two diploids results in the formation of an amphidiploid, which is not favorable.The cell-cell fusion remains poorly understood. However, it provides important experimental evidences that the cells, nuclei and DNAs from species of far relatives can fuse together and produce a hybrid cell with a new set of chromosomes. This means the two germ cells (sperms and ovules) from far relatives have more opportunity to combine and develop.
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