|
 Curently online :
1 |
|
 Total visitors :
7516864 |
|
|
From phenotype to genotype: celebrating 150 years of Mendelian genetics in plant breeding research
Thursday, 2016/12/01 | 07:57:52
|
|
Johann Vollmann, Hermann Buerstmayr Theoretical and Applied Genetics, December 2016, Volume 129, Issue 12, pp 2237–2239
In the year 1866, Gregor Mendel’s seminal publication “Versuche über Pflanzen-Hybriden” (“Experiments in Plant Hybridization”) was published in the periodical Verhandlungen des naturforschenden Vereines, Brünn, Vol 4, pp 3–47 (Mendel 1866). This marked the starting point of the science of heredity which later turned into modern genetics with a variety of sub-disciplines developing throughout the life sciences, including scientific plant and animal breeding. Dealing with discrete characters, Mendel was the first to explain phenotype ratios occurring in the progeny generations following a biparental hybridization. As genes were unknown to Mendel, he hypothesized “elements” present in pollen and egg cells as causing the heritable differences between phenotypes. In the 20th century, the concept of a gene was developed, and the gene became known as the unit of inheritance, function, recombination, and mutation (Gayon 2016).
This understanding of a gene proved to be useful for plant breeding throughout many decades and contributed to significant breeding progress in major crop species. Later, new insights from molecular genetics brought considerable changes to the concept of the gene and subsequently to plant breeding: although a more modern imagination of a gene as a coding sequence is strongly challenged by discoveries, such as split-genes, alternative splicing or the significant finding of non-coding RNA (Gayon 2016), single nucleotides within a gene became the ultimate units of interest both for selection and genetic modification. Based on advances in molecular genetics, powerful tools are currently under development for editing individual nucleotides in a gene, for selection solely based on genomic information, and for better understanding functional and regulatory genetic and epigenetic mechanisms. Apart from genomic selection, the dissection of quantitative characters through QTL analysis (Paterson et al. 1988) has particular appeal in the Mendelian context as it discloses the make-up of complex traits, each controlled by a number of individual and selectable loci behaving as Mendelian factors.
Since the rediscovery and broad recognition of Mendel at the dawn of the 20th century, different aspects on Mendel and early Mendelian genetics have been discussed across various disciplines. This includes the possible origins of Mendel’s novel approach of mathematically treating biological results (Dröscher 2015) or the ongoing debate on the precision of his experiments with segregation ratios being statistically too close to the expectations (Hartl and Fairbanks 2007; Radick 2015). Molecular genetics has provided an even deeper understanding of some of the seven traits which Mendel studied in pea: the round vs wrinkled seed shape trait is due to an 800-bp insertion into the gene coding for a starch branching enzyme causing the accumulation of sugars in the wrinkled phenotype; the tall vs dwarf stem length trait is caused by a G to A nucleotide substitution in a gibberellic acid 3-oxidase 1 gene; and the yellow vs green cotyledon color originates from a 6-bp insertion to a stay-green gene prohibiting chlorophyll degradation at maturity (Reid and Ross 2011)….
See more http://link.springer.com/article/10.1007/s00122-016-2817-9 |
Back
Print
View: 655
|
|
[ Other News ]___________________________________________________
|
