Biochemical Genetics 

About: Biochemical Genetics is an academic journal published by Springer Science+Business Media. The journal publishes majorly in the area(s): Gene & Population. It has an ISSN identifier of 0006-2928. Over the lifetime, 3775 publications have been published receiving 66345 citations.

Starch gel electrophoresis of enzymes—A compilation of recipes

Abstract: The technique of starch gel electrophoresis of enzymes with specific staining for activity in the gel, the so-called zymogram method developed by Hunter and Markert (1957), has found many research applications. Screening studies, comparing relatively large numbers of enzymes among a variety of tissues and organisms, are finding increasing use in research on population genetics, taxonomy, etc. The methods presently available are scattered through the literature. This compilation is published in response to numerous requests from investigators in many fields. Most of the methods outlined here have been used primarily for tissue extracts from mammalian species. A few have been developed only on plants or lower animals, but this is not to say that they will not work on higher organisms. The buffer systems have been for the most part empirically arrived at. All are probably subject to improvement. The techniques of making the gels and carrying out the electrophoresis are not described here. These have been amply presented in a number of publications. The vertical system is essentially that described by Shaw and Koen (1968b). The horizontal system is essentially as described by Beckman and Johnson (1964). The horizontal method has the advantage of employing simpler and less expensive apparatus, and it can be run at room temperature using ice trays to keep the gels cold. For many enzyme systems, it provides as good results as the vertical. Both Connaught starch (Connaught Laboratories, Toronto) and Electrostarch (Otto Hiller Company, Madison, Wisconsin) will give satisfactory results with either technique. Unfortunately, different batches of starch may produce varying results, both in rate of migration and in resolution; also, some batches contain substances

Genetic control of multiple molecular forms of enzymes in plants: A review

Abstract: Progress in the field of biochemical genetics of diploid organisms has been considerable in the last decade. Much of this has been made possible by the introduction of improved electrophoretic procedures utilizing various gel matrices for separation of mixtures of proteins. Investigators of genetic control of protein synthesis have effectively used this tool to estimate the number of genes involved in the production of a protein or enzyme. These methods have already proved useful in providing information as to the number of polypeptide subunits that make up a protein molecule in studies with microorganisms (Levinthal et aL, 1962), animals (Markert, 1963), and plants (Scandalios, 1965a). In conjunction with the high-resolution \"zymogram\" method for displaying enzyme activity on gels (Hunter and Markert, 1957), the gel electrophoretic procedures have afforded the geneticist a means to study mutations which presumably alter the structure of enzymes, resulting in differential electrophoretic mobilities of the molecules, while their catalytic activity is retained. This is a new and promising dimension for studying gene action, since before the advent of these techniques similar studies were essentially confined to enzyme variation due to alterations in total catalytic activity. A large number of electrophoretic variants of enzymes have now been discovered (Shaw, 1965). With these findings came the knowledge that enzymes may exist in the same organism in more than one molecular form. Such multiple molecular forms of an enzyme in~ a single organism have been designated isozymes (Markert and Moller, 1959). Isozymes may differ in primary structure because they are encoded in different genes, either allelic or nonallelic. The primary structure may be further

Genome size and the proportion of repeated nucleotide sequence DNA in plants.

Abstract: The reannealing kinetics of denatured DNA fragments from 23 species of higher plants have been studied, using hydroxylapatite chromatography to distinguish reannealed from single-stranded DNA. The 2C nuclear DNA contents of the species varied between 1.7 and 98 pg. The proportions of DNA in species with a nuclear DNA mass above 5 pg that reannealed with the kinetics of sequences present in more than 100 copies were high (69–92% with a mean of 80±2.0%). For species with less than 4 pg of DNA, the mean proportion of repeated-sequence DNA was 62±2.9%. It is concluded that most of the variation in nuclear DNA mass in higher plant chromosomes can be accounted for by variation in repeated-sequence DNA. The consequences of altering the adapted DNA content of a species by the addition of families of repeated sequences are discussed in relation to the proportion of repeated-sequence DNA.

An improved method for determining codon variability in a gene and its application to the rate of fixation of mutations in evolution

Abstract: If one has the amino acid sequences of a set of homologous proteins as well as their phylogenetic relationships, one can easily determine the minimum number of mutations (nucleotide replacements) which must have been fixed in each codon since their common ancestor. It is found that for 29 species of cytochrome c the data fit the assumption that there is a group of approximately 32 invariant codons and that the remainder compose two Poisson-distributed groups of size 65 and 16 codons, the latter smaller group fixing mutations at about 3.2 times the rate of the larger. It is further found that the size of the invariant group increases as the range of species is narrowed. Extrapolation suggests that less than 10% of the codons in a given mammalian cytochrome c gene are capable of accepting a mutation. This is consistent with the view that at any one point in time only a very restricted number of positions can fix mutations but that as mutations are fixed the positions capable of accepting mutations also change so that examination of a wide range of species reveals a wide range of altered positions. We define this restricted group as the concomitantly variable codons. Given this restriction, the fixation rates for mutations in concomitantly variable codons in cytochrome c and fibrinopeptide A are not very different, a result which should be the case if most of these mutations are in fact selectively neutral as Kimura suggests.

Biochemical diversity and evolution in the genus Mus.

Abstract: Thirteen biochemical groups of wild mice from Europe, Asia, and Africa belonging to the genus Mus are analyzed at 22–42 protein loci. Phylogenetic trees are proposed and patterns of biochemical evolution are discussed, as well as the possible contribution of wild mice to the genetic diversity of laboratory stocks.