Francis Galton, Charles Darwin’s cousin, had wide and varied interests. They ranged from exploration and travel writing to fingerprinting and the weather. After reading Darwin’s
On the Origin of ...Species
, Galton reached the conclusion that it should be possible to improve the human stock through selective breeding, as was the case for domestic animals and cultivated plants. Much of the latter half of Galton’s career was devoted to trying to devise methods to distinguish men of good stock and then to show that these qualities were inherited. But along the way he invented two important statistical methods: regression and correlation. He also discovered regression to the mean. This led Galton to believe that evolution could not proceed by the small steps envisioned by Darwin, but must proceed by discontinuous changes. Galton’s book
Natural Inheritance
(
1889
) served as the inspiration for Karl Pearson, W.F.R. Weldon and William Bateson. Pearson and Weldon were interested in continuously varying characters and the application of statistical techniques to their study. Bateson was fascinated by discontinuities and the role they might play in evolution. Galton proposed his Law of Ancestral Heredity in the last decade of the nineteenth century. At first this seemed to work well as an explanation for continuously varying traits of the type that interested Pearson and Weldon. In contrast, Bateson had published a book on discontinuously varying traits so he was in a position to understand and embrace Mendel’s principles of inheritance when they were rediscovered in 1900. The subsequent battle between Weldon and Pearson, the biometricians, and Bateson, the Mendelian, went on acrimoniously for several years at the beginning of the twentieth century before Mendelian theory finally won out.
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The eugenics movement was initiated by Sir Francis Galton, a Victorian
scientist. Galton's career can be divided into two parts. During the
first, Galton was engaged in African exploration, travel ...writing, geography,
and meteorology. The second part began after he read the
Origin of
Species
by his cousin Charles Darwin. The book convinced Galton that
humanity could be improved through selective breeding. During this part of his
career he was interested in the factors that determine what he called human
"talent and character" and its hereditary basis. Consequently, he
delved into anthropometrics and psychology and played a major role in the
development of fingerprinting. He also founded the field of biometrics,
inventing such familiar statistical procedures as correlation and regression
analysis. He constructed his own theory of inheritance in which nature and not
nurture played the leading role. He actively began to promote eugenics and soon
gained important converts.
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Few scientists have made lasting contributions to as many fields as Francis Galton. He was an important African explorer, travel writer, and geographer. He was the meteorologist who discovered the ...anticyclone, a pioneer in using fingerprints to identify individuals, the inventor of regression and correlation analysis in statistics, and the founder of the eugenics movement. Now, Nicholas Gillham paints an engaging portrait of this Victorian polymath. The book traces Galton’s ancestry (he was the grandson of Erasmus Darwin and the cousin of Charles Darwin), upbringing, training as a medical apprentice, and experience as a Cambridge undergraduate. It recounts in colorful detail Galton’s adventures as leader of his own expedition in Namibia. Darwin was always a strong influence on his cousin and a turning point in Galton’s life was the publication of the Origin of Species. Thereafter, Galton devoted most of his life to human heredity, using then novel methods such as pedigree analysis and twin studies to argue that talent and character were inherited and that humans could be selectively bred to enhance these qualities. To this end, he founded the eugenics movement which rapidly gained momentum early in the last century. After Galton’s death, however, eugenics took a more sinister path, as in the United States, where by 1913 sixteen states had involuntary sterilization laws, and in Germany, where the goal of racial purity was pushed to its horrific limit in the “final solution.” Galton himself, Gillham writes, would have been appalled by the extremes to which eugenics was carried. Here then is a vibrant biography of a remarkable scientist as well as a superb portrait of science in the Victorian era.
We have constructed a dominant selectable marker for nuclear transformation of C. reinhardtii, composed of the coding sequence of the eubacterial aadA gene (conferring spectinomycin resistance) fused ...to the 5' and 3' untranslated regions of the endogenous RbcS2 gene. Spectinomycin-resistant transformants isolated by direct selection (1) contain the chimeric gene(s) stably integrated into the nuclear genome, (2) show cosegregation of the resistance phenotype with the introduced DNA, and (3) synthesize the expected mRNA and protein. Small linearized plasmids appeared to be inserted into the nuclear genome preferentially through their ends, with relatively few large deletions and/or rearrangements. Multiple copy transformants often integrated concatemers of transforming DNA. Our detailed analysis of the complex integration patterns of plasmid DNA in C. reinhardtii nuclear transformants should be useful for improving the technique of insertional mutagenesis. We also found that the spectinomycin-resistance phenotype was unstable in about half of the transformants. When maintained under nonselective conditions, neither the aadA mRNA nor the AadA protein were detected in these subclones. Moreover, since the integrated transforming DNA was not altered or lost, expression of the RbcS2::aadA::RbcS2 gene(s) appears to be repressed. Measurements of transcriptional activity, mRNA accumulation, and mRNA stability suggest that expression of this chimeric gene(s) may also be affected by rapid RNA degradation, presumably due to defects in mRNA processing and/or nuclear export. Thus, both gene silencing and transcript instability, rather than biased codon usage, may explain the difficulties encountered in the expression of foreign genes in the nuclear genome of Chlamydomonas
Consistent with their postulated origin from endosymbiotic cyanobacteria, chloroplasts of plants and algae have ribosomes whose component RNAs and proteins are strikingly similar to those of ...eubacteria. Comparison of the secondary structures of 16S rRNAs of chloroplasts and bacteria has been particularly useful in identifying highly conserved regions likely to have essential functions. Comparative analysis of ribosomal protein sequences may likewise prove valuable in determining their roles in protein synthesis. This review is concerned primarily with the RNAs and proteins that constitute the chloroplast ribosome, the genes that encode these components, and their expression. It begins with an overview of chloroplast genome structure in land plants and algae and then presents a brief comparison of chloroplast and prokaryotic protein-synthesizing systems and a more detailed analysis of chloroplast rRNAs and ribosomal proteins. A description of the synthesis and assembly of chloroplast ribosomes follows. The review concludes with discussion of whether chloroplast protein synthesis is essential for cell survival.
Francis Galton frequently disagreed with his cousin Charles Darwin concerning the mechanism of evolutionary change. Gillham discusses Galton's career and he describes how Galton and William Bateson, ...another evolution enthusiast, came to the conclusion that evolution must proceed in discontinuous steps.
Transfer of Chlamydomonas reinhardtii cells grown photoautotrophically in low light to higher light intensities has a dramatic transient effect on the differential expression of the two major ...chloroplast encoded photosynthetic proteins. Synthesis of the D1 protein of Photosystem II increases more than 10-fold during the first six hours in high light (HL), whereas synthesis of the large subunit (LSU) of Rubisco drops dramatically within 15 min and only gradually resumes at about 6 h. Synthesis of the chloroplast-encoded ATP synthase beta subunit, the nuclear-encoded Rubisco small subunit and the nuclear-encoded beta-tubulin is not noticeably affected. Up regulation of psbA mRNA translation accounts for a substantial fraction of the increased D1 synthesis, since accumulation of psbA mRNA increases 4.2- and 6.3-fold less than D1 synthesis at 6 and 18 h in HL. Down-regulation of LSU synthesis is not correlated with a reduction in the steady-state level of the rbcL transcript. Primer extension mapping of the 5' ends of the rbcL mRNAs reveals transcripts with start points located at -93 and -168 relative to the first translated ATG. Transfer of low light (LL)-grown cells to HL temporarily decreases the ratio of the -93 to -168 transcripts, but this ratio normalizes after 6 h in HL, coincident with the recovery in the synthesis of LSU. These several distinct effects of temporary light stress were correlated with a rapid, sustained increase in the reduction state of QA, a transient decline in photosynthetic efficiency, a less rapid drop in total chlorophyll content and a delay in cell division.
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