hereditary variation
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2021 ◽  
Vol 910 (1) ◽  
pp. 012110
Author(s):  
Majid A. S. Al-Neemy ◽  
Esraa Mohammed Tawfeq ◽  
Haitham Mohammed Sabeeh Hadi

Abstract The main objective of this research was to specify the hereditary variation associated with the plumage color in three local genotypes of Japanese quail which bred in two geographical locations. The birds distributed on six treatments with five birds for each depending on the feather's color and geographical locations. DNA extraction was executed from the blood samples of each treatment and amplified by thermo cycler apparatus and the electrophoresis was done using 1.5% agarose gel for DNA bands exhibiting. Genotype influence has been shown that the black color quail B1 of the agricultural research station in the city of Mosul showed maximum genetic similarity with the Black quail B2 of Tikrit University with a value of 0.9549, the highest genetic similarity between different colors found between B1 and W2 that amounted to 0.9391 based on the similarity index (band sharing). While, the least genetic similarity observed between B2 and W1, which went down to 0.8468. Genetic difference values among studied quail groups showed that the groups B2 and W1 in the higher genetic variation, whereas the least genetic difference found between B1 and B2 groups. The average of dissimilarities for each group with all others varied between the values 0.1203 - 0.0851. The present work prove that the effectiveness of RAPD markers in knowing the similarity and specify the inherited relationship within the quail varieties.


Genetics ◽  
2020 ◽  
Vol 215 (2) ◽  
pp. 291-296
Author(s):  
Ehud Lamm ◽  
Oren Harman ◽  
Sophie Juliane Veigl

In 1869, the young Swiss biochemist Friedrich Miescher discovered the molecule we now refer to as DNA, developing techniques for its extraction. In this paper we explain why his name is all but forgotten, and his role in the history of genetics is mostly overlooked. We focus on the role of national rivalries and disciplinary turf wars in shaping historical memory, and on how the story we tell shapes our understanding of the science. We highlight that Miescher could just as correctly be portrayed as the person who understood the chemical nature of chromatin (before the term existed), and the first to suggest how stereochemistry might serve as the basis for the transmission of hereditary variation.


Author(s):  
Anya Plutynski

Huxley coined the phrase, the ‘modern synthesis’ to refer to the acceptance by a vast majority of biologists in the mid-twentieth century of a ‘synthetic’ view of evolution. According to its main chroniclers, Mayr and Provine, the ‘synthesis’ consisted in the acceptance of natural selection acting on minor hereditary variation as the primary cause of both adaptive change within populations and major changes, such as speciation, and the evolution of higher taxa (e.g. families and genera). However, the dating and substance of the synthesis is controversial. The evolutionary synthesis may be broken down into two periods, the ‘early’ synthesis from 1918 to 1932, and the later, ‘modern synthesis’ from 1936 to 1947. The authors most commonly associated with the early synthesis are J. B. S. Haldane, R. A. Fisher, and S. Wright. These three authored a number of important advances; first, they demonstrated the compatibility of a Mendelian theory of inheritance with the results of Biometry, a study of the correlations of measures of traits between relatives. Second, they developed the theoretical framework for evolutionary biology, classical population genetics. This is a family of mathematical models representing evolution as change in genotype frequencies, from one generation to the next, as a product of selection, mutation, migration, and drift, or chance. Third, there was a broader synthesis of population genetics with cytology (cell biology), genetics, and biochemistry, as well as both empirical and mathematical demonstrations to the effect that very small selective forces acting over a relatively long time were able to generate substantial evolutionary change. The later ‘modern’ synthesis is most often identified with the work of Mayr, Dobzhansky and Simpson. There was a major institutional change in biology at this stage, insofar as different subdisciplines formerly housed in different departments, and using different methods, were united under the institutional umbrella of ‘evolutionary biology’. Mayr played an important role as a community architect, in founding the Society for the Study of Evolution, and the journal Evolution, which drew together work in systematics, biogeography, paleontology, and theoretical population genetics. The synthesis presents an occasion for addressing a number of important philosophical questions about the nature of theories, explanation, progress in science, theory unification, and reduction.


2012 ◽  
Vol 367 (1603) ◽  
pp. 2677-2685 ◽  
Author(s):  
Lars Chittka ◽  
Stephen J. Rossiter ◽  
Peter Skorupski ◽  
Chrisantha Fernando

To understand how complex, or ‘advanced’ various forms of cognition are, and to compare them between species for evolutionary studies, we need to understand the diversity of neural–computational mechanisms that may be involved, and to identify the genetic changes that are necessary to mediate changes in cognitive functions. The same overt cognitive capacity might be mediated by entirely different neural circuitries in different species, with a many-to-one mapping between behavioural routines, computations and their neural implementations. Comparative behavioural research needs to be complemented with a bottom-up approach in which neurobiological and molecular-genetic analyses allow pinpointing of underlying neural and genetic bases that constrain cognitive variation. Often, only very minor differences in circuitry might be needed to generate major shifts in cognitive functions and the possibility that cognitive traits arise by convergence or parallel evolution needs to be taken seriously. Hereditary variation in cognitive traits between individuals of a species might be extensive, and selection experiments on cognitive traits might be a useful avenue to explore how rapidly changes in cognitive abilities occur in the face of pertinent selection pressures.


2012 ◽  
Vol 18 (2) ◽  
pp. 129-142 ◽  
Author(s):  
Nathaniel Virgo ◽  
Chrisantha Fernando ◽  
Bill Bigge ◽  
Phil Husbands

Building an evolvable physical self-replicating machine is a grand challenge. The main problem is that the device must be capable of hereditary variation, that is, replicating in many configurations—configurations into which it enters unpredictably by mutation. Template replication is the solution found by nature. A scalable device must also be capable of miniaturization, and so have few or no moving and electronic parts. Here a significant step toward this goal is presented in the form of a physical template replicator made from small plastic pieces containing embedded magnets that float on an air-hockey-type table and undergo stochastic motion. Our units replicate by a process analogous to the replication of DNA, except without the involvement of enzymes. Building a physical rather than a computational model forces us to confront several problems that have analogues on the nano scale. In particular, replication must be maintained by preventing side reactions such as spontaneous ligation, cyclization, product inhibition, and elongation at staggered ends. The last of these results in ever-lengthening sequences in a process known as the elongation catastrophe. The extreme specificity of structure required by the monomers is indirect evidence that some kind of natural selection took place prior to the existence of nucleotide analogues during the origin of life.


2007 ◽  
Vol 30 (4) ◽  
pp. 353-365 ◽  
Author(s):  
Eva Jablonka ◽  
Marion J. Lamb

AbstractIn his theory of evolution, Darwin recognized that the conditions of life play a role in the generation of hereditary variations, as well as in their selection. However, as evolutionary theory was developed further, heredity became identified with genetics, and variation was seen in terms of combinations of randomly generated gene mutations. We argue that this view is now changing, because it is clear that a notion of hereditary variation that is based solely on randomly varying genes that are unaffected by developmental conditions is an inadequate basis for evolutionary theories. Such a view not only fails to provide satisfying explanations of many evolutionary phenomena, it also makes assumptions that are not consistent with the data that are emerging from disciplines ranging from molecular biology to cultural studies. These data show that the genome is far more responsive to the environment than previously thought, and that not all transmissible variation is underlain by genetic differences. In Evolution in Four Dimensions (2005) we identify four types of inheritance (genetic, epigenetic, behavioral, and symbol-based), each of which can provide variations on which natural selection will act. Some of these variations arise in response to developmental conditions, so there are Lamarckian aspects to evolution. We argue that a better insight into evolutionary processes will result from recognizing that transmitted variations that are not based on DNA differences have played a role. This is particularly true for understanding the evolution of human behavior, where all four dimensions of heredity have been important.


2004 ◽  
Vol 40 (11) ◽  
pp. 1239-1244 ◽  
Author(s):  
V. P. Netsvetaev ◽  
O. V. Netsvetaeva

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