REVIEW | doi:10.20944/preprints202007.0328.v3
Subject: Biology, Other Keywords: Evolution; Speciation; Crossbreeding; Hybridization; Species spectrum; Polyploidization; Somatic cell hybridization; Mutation
Online: 3 March 2022 (10:25:51 CET)
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.
REVIEW | doi:10.20944/preprints202201.0342.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: Anthocyanin biosynthesis; biosafety regulations; colored vegetables; crossbreeding; gene editing; human health; transgenes
Online: 24 January 2022 (10:38:22 CET)
Malnutrition, unhealthy diets, and lifestyle changes have become major risk factors for non-communicable diseases while ad-versely impacting economic growth and sustainable development. Anthocyanins, a group of flavonoids that are rich in fruits and vegetables, contribute positively to human health. This review focuses on genetic variation harnessed through crossbreeding and biotechnology-led approaches for developing anthocyanins-rich fruit and vegetable crops. Significant progress has been made in identifying genes involved in anthocyanin biosynthesis in various crops. Thus, the use of genetics has led to the development and release of anthocyanin-rich crop cultivars in Europe and USA. Such a trend is emerging in the developing world. The purple pota-to “Kufri Neelkanth” has been released for cultivation in northern India, and a few colored grain wheat lines, developed through crossbreeding, are being tested for their productivity and adaptation. Although tomato is deficient in anthocyanins, some of its wild relatives are known to accumulate anthocyanins in their sub-epidermal fruit tissue. In Europe, anthocyanin-rich tomato cul-tivar ‘Sun Black’ developed via the introgression of Aft and atv genes has been released. The development of anthocyanin-rich food crops without any significant yield penalty has been due to the use of genetic engineering involving specific transcription factors or gene editing. The anthocyanin-rich food ingredients have the potential of being more nutritious than those devoid of anthocyanins. The inclusion of anthocyanins as a target characteristic in breeding programs can ensure the development of culti-vars to meet the nutritional needs for human consumption, particularly in the developing world.