The Road to Gattaca 1
Tina Stevens, Stuart Newman in Biotech Juggernaut, 2019
Because it would involve experimentation with irreversible consequences, based on incomplete knowledge of genes (with the very concept of the gene being questioned), germline alteration is the “red line” that many have felt should not be crossed. The term “germline” emphasizes the fact that engineering embryos would typically cause transmission of genetic alterations to all future offspring of the engineered person. Although germline alteration dominates discussions about human genetic modification, this aspect would not be the most profound cultural watershed represented by the procedure. Once we accept the engineering of prospective people, even without germline propagation, something unprecedented in the history of human civilization occurs: the trial-and-error-based quality control ethos of industrial manufacturing becomes part of human procreation.
Cascade Regulation a Model of Integrative Control of Gene Expression in Eukaryotic Cells and Organisms
M. Gerald, M.D. Kolodny in Eukaryotic Gene Regulation, 2018
In fact, in accordance with the fundamentalistic aspiration of our analysis, the term “genome” must be more closely defined. Recent experimental facts as well as theoretical consideration demonstrate the ambiguity of the classical equation that cellular DNA equals genome. Although one may still postulate that the germ-line DNA is the physical carrier of the “genome” of a species, prior to its possible rearrangements during the processes leading to the DNA of an individual somatic cell, this definition includes, however, two flaws: (1) the zygote, i.e., the entity of mature oocyte and sperm, may contain more information than the DNA contained therein, and (2) theoretically, the totality of genetic information of a species, within the frame of the possibilities of sexual interaction at genetical level, contains more information than the germ-line genome of an individual. For rigor of logics we have, therefore, to make a distinction between the “genome” of the species and that of an individual organism or of a cell.
JAK-STAT pathway: Testicular development, spermatogenesis and fertility
Rajender Singh in Molecular Signaling in Spermatogenesis and Male Infertility, 2019
There are two existing cell populations in Drosophila that include germline and somatic cells. How do these cells achieve sexual identity? In Drosophila somatic cells, male and female identity is defined by counting the ratio of X chromosome to an autosome, where an X/A ratio of 1 indicates normal female and X/A ratio of 0.5 indicates normal male (42). There is a double copy of X-linked signal elements (XSEs) in females as compared to males. These X-linked elements include sisterless-a (sis-a), scute (sis-b), runt (run) which encodes transcription factor and unpaired (sisterless-c) which encodes a secretory ligand (16,42). These double copies of XSEs are important for regulating the transcription of Sxl (sex-lethal) from Sxl-pe (promoter for the establishment) in females. The resultant protein from Sxl-pe regulates its own synthesis from Sxl-pm promoter (promoter for maintenance). Thus, Sex-lethal is turned on only in females. Sxl acts through a transformer (tra) and regulates splicing of doublesex RNA (dsx) in females. But in males, because Sxl is not present, default Splicing of dsx results in males (Figure 15.5). Another ligand, Upd, is considered to be a weak XSE because Upd and other downstream components, such as Hop and STAT92E, in mutational studies had little effect on Sxl expression in females (43–46).
Germline mosaicism in a DMD family: incidental identification in prenatal diagnosis
Published in Journal of Obstetrics and Gynaecology, 2018
Germline mosaicism can occur with any inheritance pattern, but it is most commonly observed in autosomal dominant and X-linked disorders (Edwards 1989). A mosaic germline mutation is significant because it can be obscurely passed to offspring. Most individuals are unaware of a naturally occurring germline mutation until they have a child who is affected. Duchenne Muscular Dystrophy (DMD) is a severe X-linked neuromuscular disease with an incidence of approximately 1 in 3500 newborn boys. The DMD locus has a high mutation frequency: one-third of mutations are de novo, and two-thirds are inherited from carrier mothers (Lee et al. 2014). Instances of germinal mosaicism have been elucidated in DMD families on the basis of more than one affected offspring born to an apparently non-carrier parent (Bermúdez-López et al. 2014). Here we report on germline mosaicism in a DMD family incidentally identified in prenatal diagnosis by using chromosomal microarray analysis (CMA).
Is It All About Revising, Correcting, and Transferring Genes?
Published in The American Journal of Bioethics, 2020
Vasilija Rolfes, Uta Bittner, Heiner Fangerau, Karsten Weber
To illustrate our proposal, we refer to the argument that germline interventions could contribute to a possible selection of certain traits, ensuring that only embryos (and thus children) with these desired traits would be produced, because they are considered healthy and “favourable.” Their genetic health would then be passed on to future generations (Ormond et al. 2017, 172). Consequently, this technology might lead to discrimination against people with certain genetic variations and traits and contribute to heteronomy, as Habermas (2003) suggested. Cwik is aware of such slippery slope arguments and suggests ways in which they can be overcome; however, we consider these to be insufficient. His distinction between pathogenic/non-pathogenic appears to be based on statistical considerations, where there is at least the risk of an “is-ought” problem: because the majority of the population is genetically composed in one way or another, this establishes a valid normative standard. From an ethical point of view, this seems precarious.
Evolutionary life history theory as an organising framework for cohort studies: insights from the Cebu Longitudinal Health and Nutrition Survey
Published in Annals of Human Biology, 2020
Christopher W. Kuzawa, Linda Adair, Sonny A. Bechayda, Judith Rafaelita B. Borja, Delia B. Carba, Paulita L. Duazo, Dan T. A. Eisenberg, Alexander V. Georgiev, Lee T. Gettler, Nanette R. Lee, Elizabeth A. Quinn, Stacy Rosenbaum, Julienne N. Rutherford, Calen P. Ryan, Thomas W. McDade
While increasing reproductive effort during early adulthood may accelerate blood telomere shortening in females, the dynamics of telomere length in the germline allow for a unique form of intergenerational genetic plasticity that could link male reproduction to patterns of life history allocation in future generations. Telomere length shortens with age in most human tissues, but spermatocyte telomere length increases with age (Eisenberg and Kuzawa 2018), which appears to be driven by the continuous production of sperm in the presence of high levels of testicular telomerase (an enzyme that lengthens telomeres). Correspondingly, offspring of older fathers have longer telomere length (Eisenberg and Kuzawa 2018). Our work with the CLHNS demonstrated that this effect of paternal age at conception persists cumulatively across at least two generations – that is, the age at which paternal grandfathers sired fathers and maternal grandfathers sired mothers predicts the grandchild’s telomere length additively and independently to the effect of their own father’s age on their telomere length (Eisenberg et al. 2012, 2019).
Related Knowledge Centers
- Egg Cell
- Multicellular Organism
- Sexual Reproduction
- Sperm
- Cellular Differentiation
- Meiosis
- Genetics
- Offspring
- Zygote
- Genetic Recombination