Conceptual change and scientific progress in genetics

Akbay, Gökhan
In this thesis, the historical origins and the contemporary status of the gene centric perspective is evaluated. Gene centrism is a viewpoint which is characterized by the emphasis on genes in the explanation of phenotypes. Gene centric perspective has been defended on the grounds that only genes bear information that specifies organisms. The information concept, as it is used in biology, is problematic. Gene centrism cannot be grounded on a problematic concept of information. The real power of gene centrism depends on the success of genetic analysis as a method for investigating biological phenomena, rather than a fundamental theory based on the concept of information. Complex phenoptypes and their genetic bases, for which genetic analysis reaches its limit, provide clues for how the limits of gene centrism would be transgressed. 


Development of a genetic material transfer approach for gene therapy
Ayaz, Şerife; Hasırcı, Vasıf Nejat; Department of Biotechnology (2005)
This thesis is focused on the development of a gene delivery system, especially for the purpose of DNA vaccination. DNA expression vectors have the potential to be useful therapeutics for a wide variety of applications. A carrier system was designed to realize the delivery of genes to cells and the promotion of controlled adequate expression in the target cells. The low gene delivery efficiency observed with systems composed of polyplexes is mainly due to low stability of polycation e.g polyethylenimine-DNA...
Functional characterization of microrna-125b expression in MCF7 breast cancer cell line
Tuna, Serkan; Erson Bensan, Ayşe Elif; Department of Biology (2010)
microRNA dependent gene expression regulation has roles in diverse processes such as differentiation, proliferation and apoptosis. Therefore, deregulated miRNA expression has functional importance for various diseases, including cancer. miR-125b is among the commonly downregulated miRNAs in breast cancer cells . Therefore we aimed to characterize the effects of miR-125b expression in MCF7 breast cancer cell line (BCCL) to better understand its roles in tumorigenesis. Here, we investigated mir-125 family mem...
Evolution of Primate Gene Expression: Drift and Corrective Sweeps?
Chaix, R.; Somel, Mehmet; Kreil, D. P.; Khaitovich, P.; Lunter, G. A. (Genetics Society of America, 2008-11-01)
Changes in gene expression play an important: role in species' evolution. Earlier studies uncovered evidence that the effect of mutations on expression levels within the primate order is skewed, with many small downregulations balanced by fewer but larger upregulations. In addition, brain-expressed genes appeared to show an increased rate of evolution on the branch leading to human. However, the lack of a mathematical model adequately describing the evolution of gene expression precluded the rigorous establ...
Identification and analysis of genomic regions with large between-population differentiation in humans
Myles, S.; Tang, K.; Somel, Mehmet; Green, R. E.; Kelso, J.; Stoneking, M. (Wiley, 2008-01-01)
The primary aim of genetic association and linkage studies is to identify genetic variants that contribute to phenotypic variation within human populations. Since the overwhelming majority of human genetic variation is found within populations, these methods are expected to be effective and can likely be extrapolated from one human population to another. However, they may lack power in detecting the genetic variants that contribute to phenotypes that differ greatly between human populations. Phenotypes that...
A novel approach for small sample size family-based association studies: sequential tests
İlk Dağ, Özlem; Dungul, Dilay Ciglidag; ÖZDAĞ, Hilal; İLK, HAKKI GÖKHAN (Springer Science and Business Media LLC, 2011-08-01)
In this paper, we propose a sequential probability ratio test (SPRT) to overcome the problem of limited samples in studies related to complex genetic diseases. The results of this novel approach are compared with the ones obtained from the traditional transmission disequilibrium test (TDT) on simulated data. Although TDT classifies single-nucleotide polymorphisms (SNPs) to only two groups (SNPs associated with the disease and the others), SPRT has the flexibility of assigning SNPs to a third group, that is,...
Citation Formats
G. Akbay, “Conceptual change and scientific progress in genetics,” Ph.D. - Doctoral Program, Middle East Technical University, 2016.