Transformation of immature wheat germ (Triticum aestivum L.) by particle bombardment

The aim of the research was to create an effective method for producing transgenic wheat plants suitable for a wide range of promising varieties, both spring and winter crops. The plant material was cultivated at temperatures ranging from 4 to 25°C, either in the dark or in the light, with a 16-hour photoperiod (16/8 - day / night). Osram L36/77 FLUORA and F36W/33 Cool White lamps were used for lighting. The composition of all nutrient media included macroand micro-salts, vitamins B5, phytohormones and carbohydrates. The pH of the medium was adjusted to 5.8 before autoclaving. The medium was sterilized in an autoclave at pressure of 1.2 atmospheres for 15 minutes. An effective method of regeneration of transgenic wheat plants for ballistic transformation has been developed. Plants obtained by this method are phenotypically normal and fully fertile. The transgenic insertion of the target gene is transmitted to the offspring in accordance with Mendel’s laws. The transformation efficiency was high for all the studied varieties and ranged from 1.4 to 7.8%.

Medical Bacteriology and Medical Genetics, 1880–1940: A Call for Synthesis

Between 1880 and 1920 the medical quest to unearth the causes of disease saw two pathbreaking discoveries. One was the bacteriological revolution – the identification of specific germs as causal agents of specific diseases (anthrax, tuberculosis, diphtheria, cholera and so on), and the simultaneous effort to develop disinfection techniques and immunisation measures to combat these diseases. The other was the rediscovery of Mendel’s laws of heredity and the resulting emergence of medical genetics, where an entire set of medical maladies (deafness, blindness, bodily deformities, haemophilia, Huntington’s chorea, feeble-mindedness and many mental diseases) were identified – rightly or wrongly – as genetically determined. The ‘germ theory of disease’ and the ‘gene theory of disease’ shared striking, all-too-often overlooked similarities. Both theories built on shared epistemological assumptions that influenced their explanatory mechanisms and their overall conceptual frameworks; both mobilised similar visual and linguistic vocabulary; both appropriated – and enforced – prevailing cultural and gender norms; and both enshrined broadly parallel hygienic practices. Reflecting similar social concerns, medical bacteriology and medical genetics acquired kindred scientific and societal configurations, which this paper highlights and scrutinises.

The establishment of the fertile fish lineages derived from distant hybridization by overcoming the reproductive barriers

Distant hybridization refers to the cross between two different species or higher-ranking taxa. It is very significant if the new lineages with genetic variation, fertile ability, and improved characteristics can be established through distant hybridization. However, reproductive barriers are key limitations that must be overcome to establish fertile lineages derived from distant hybridization. In the present review, we discussed how distant hybridization is an important way to form new species by overcoming reproductive barriers and summarized effective measures to overcome reproductive barriers in order to create fertile lineages of fish distant hybridization. In addition, we described the utilization of the fish lineages derived from distant hybridization. Finally, we discussed the relationship between distant hybridization and Mendel’s laws, which generally apply to the inbred hybridization. We aim to provide a comprehensive reference for the establishment of fertile fish lineages by overcoming reproductive barriers and to emphasize the significance of fish distant hybridization in the fields of evolutionary biology, reproductive biology, and genetic breeding.

Genetics

Genetics studies the problem of heredity, namely why offspring resemble their parents. The field emerged in 1900 with the rediscovery of the 1865 work of Gregor Mendel. William Bateson called the new field ‘genetics’ in 1905, and W. Johannsen used the term ‘gene’ in 1909. By analysing data about patterns of inheritance of characters, such as yellow and green peas, Mendelian geneticists infer the number and type of hypothetical genes. The major components of the theory of the gene, which proposed the model of genes as beads on a string, were in place by the 1920s. In the 1930s, the field of population genetics emerged from the synthesis of results from Mendelian genetics with Darwinian natural selection. Population geneticists study the distribution of genes in the gene pool of a population and changes caused by selection and other factors. The 1940s and 1950s saw the development of molecular genetics, which investigates problems about gene reproduction, mutation and function at the molecular level. Philosophical issues arise: the question about the evidence for the reality of hypothetical genes, and the status of Mendel’s laws, given that they are not universal generalizations. Debates have occurred about the nature of the relation between Mendelian and molecular genetics. Population genetics provides the perspective of the gene as the unit of selection in evolutionary theory. Molecular genetics and its accompanying technologies raise ethical issues about humans’ genetic information, such as the issue of privacy of information about one’s genome and the morality of changing a person’s genes. The nature–nurture debate involves the issue of genetic determinism, the extent to which genes control human traits and behaviour.