scholarly journals Reproductive Isolation and Morphogenetic Evolution in Drosophila Analyzed by Breakage of Ethological Barriers

Genetics ◽  
1997 ◽  
Vol 147 (1) ◽  
pp. 231-242 ◽  
Author(s):  
Lucas Sánchez ◽  
Pedro Santamaria
Keyword(s):  
Reproductive Isolation ◽  
Germ Cells ◽  
Morphological Analysis ◽  
Seminal Fluid ◽  
Germ Line ◽  
Regulatory Gene ◽  
Motile Sperm ◽  
Male And Female ◽  
Drosophila Yakuba

Abstract This article reports the breaking of ethological barriers through the constitution of soma-germ line chimeras between species of the melanogaster subgroup of Drosophila, which are ethologically isolated. Female Drosophila yakuba and D. teissieri germ cells in a D. melanogaster ovary produced functional oocytes that, when fertilized by D. melanogaster sperm, gave rise to sterile yakuba-melanogaster andteissieri-melanogaster male and female hybrids. However, the erecta-melanogaster and orena-melanogaster hybrids were lethal, since female D. erecta and D. orena germ cells in a D. melanogaster ovary failed to form oocytes with the capacity to develop normally. This failure appears to be caused by an altered interaction between the melanogaster soma and the erecta and orena germ lines. Germ cells of D. teissieri and D. orena in a D. melanogaster testis produced motile sperm that was not stored in D. melanogaster females. This might be due to incompatibility between the teissieri and orena sperm and the melanogaster seminal fluid. A morphological analysis of the terminalia of yakuba-melanogaster and teissieri-melanogaster hybrids was performed. The effect on the terminalia of teissieri-melanogaster hybrids of a mutation in doublesex, a regulatory gene that controls the development of the terminalia, was also investigated.

scholarly journals Fine-tuning evolution: germ-line epigenetics and inheritance

Reproduction ◽  
2013 ◽  
Vol 146 (1) ◽  
pp. R37-R48 ◽  
Author(s):  
Jessica M Stringer ◽  
Sanna Barrand ◽  
Patrick Western
Keyword(s):  
Germ Cells ◽  
Cell Function ◽  
Germ Line ◽  
Primordial Germ Cells ◽  
Epigenetic Reprogramming ◽  
Fine Tuning ◽  
Male And Female ◽  
Epigenetic Information

In mice, epiblast cells found both the germ-line and somatic lineages in the developing embryo. These epiblast cells carry epigenetic information from both parents that is required for development and cell function in the fetus and during post-natal life. However, germ cells must establish an epigenetic program that supports totipotency and the configuration of parent-specific epigenetic states in the gametes. To achieve this, the epigenetic information inherited by the primordial germ cells at specification is erased and new epigenetic states are established during development of the male and female germ-lines. Errors in this process can lead to transmission of epimutations through the germ-line, which have the potential to affect development and disease in the parent's progeny. This review discusses epigenetic reprogramming in the germ-line and the transmission of epigenetic information to the following generation.

scholarly journals Impact of oxidative stress on male and female germ cells: implications for fertility

Reproduction ◽  
2020 ◽  
Vol 159 (4) ◽  
pp. R189-R201 ◽  
Author(s):  
R John Aitken
Keyword(s):  
Oxidative Stress ◽  
Oxidative Damage ◽  
Germ Cells ◽  
Germ Line ◽  
Reproductive Function ◽  
Oocyte Quality ◽  
Ros Generation ◽  
Male And Female ◽  
Developmental Capacity ◽  
Lipid Aldehydes

Male and female germ lines are vulnerable to oxidative stress. In spermatozoa, such stress triggers a lipid peroxidation cascade that culminates in the generation of electrophilic lipid aldehydes that bind to DNA and a raft of proteins involved in the delivery of functionally competent cells. One set of targets for these aldehydes are the proteins of the mitochondrial electron transport chain. When this interaction occurs, mitochondrial ROS generation is enhanced leading to the sustained generation of oxidative damage in a self-perpetuating cycle. Such damage affects all aspects of sperm function including motility, sperm-egg recognition, acrosomal exocytosis and sperm-oocyte fusion. Oxidative stress in the male germ line also attacks the integrity of sperm DNA with potential impacts on the developmental capacity of embryos and the health and wellbeing of the offspring. Potential pathways of reactive oxygen species (ROS) generation in male germ cells could involve enhanced lipoxygenase activity, activation of NADPH oxidase and/or electron leakage from mitochondria. Similarly, in the female germ line, both the induction of oocyte senescence following ovulation and the deterioration of oocyte quality with maternal age appear to involve the generation of oxidative damage. In this case, the mitochondria appear to be a particularly important source of ROS compromising the viability and fertilizability of the oocyte and interfering with the normal segregation of chromosomes during meiosis. In light of these considerations, antioxidants should have some role to play in the preservation of reproductive function in both men and women; however, we still await appropriate trials to test this hypothesis.

scholarly journals Apoptosis in the germ line

Reproduction ◽  
2011 ◽  
Vol 141 (2) ◽  
pp. 139-150 ◽  
Author(s):  
R John Aitken ◽  
Jock K Findlay ◽  
Karla J Hutt ◽  
Jeff B Kerr
Keyword(s):  
Stem Cells ◽  
Cell Death ◽  
Germ Cells ◽  
Germ Line ◽  
Reproductive Potential ◽  
Male And Female ◽  
Primordial Follicles ◽  
Mature Gonad ◽  
Critical Process

Apoptosis is a critical process for regulating both the size and the quality of the male and female germ lines. In this review, we examine the importance of this process during embryonic development in establishing the pool of spermatogonial stem cells and primordial follicles that will ultimately define male and female fertility. We also consider the importance of apoptosis in controlling the number and quality of germ cells that eventually determine reproductive success. The biochemical details of the apoptotic process as it affects germ cells in the mature gonad still await resolution, as do the stimuli that persuade these cells to commit to a pathway that leads to cell death. Our ability to understand and ultimately control the reproductive potential of male and female mammals depends upon a deeper understanding of these fundamental processes.

scholarly journals glp-3 Is Required for Mitosis and Meiosis in the Caenorhabditis elegans Germ Line

Genetics ◽  
1997 ◽  
Vol 145 (1) ◽  
pp. 111-121 ◽  
Author(s):  
Lisa C Kadyk ◽  
Eric J Lambie ◽  
Judith Kimble
Keyword(s):  
Caenorhabditis Elegans ◽  
Germ Cells ◽  
Germ Line ◽  
Stem Cell Population ◽  
Phenotypic Characterization ◽  
Loss Of Function ◽  
Dapi Staining ◽  
Cell Cycles ◽  
C Elegans ◽  
Mitosis And Meiosis

The germ line is the only tissue in Caenorhabditis elegans in which a stem cell population continues to divide mitotically throughout life; hence the cell cycles of the germ line and the soma are regulated differently. Here we report the genetic and phenotypic characterization of the glp-3 gene. In animals homozygous for each of five recessive loss-of-function alleles, germ cells in both hermaphrodites and males fail to progress through mitosis and meiosis, but somatic cells appear to divide normally. Germ cells in animals grown at 15° appear by DAPI staining to be uniformly arrested at the G2/M transition with <20 germ cells per gonad on average, suggesting a checkpoint-mediated arrest. In contrast, germ cells in mutant animals grown at 25° frequently proliferate slowly during adulthood, eventually forming small germ lines with several hundred germ cells. Nevertheless, cells in these small germ lines never undergo meiosis. Double mutant analysis with mutations in other genes affecting germ cell proliferation supports the idea that glp-3 may encode a gene product that is required for the mitotic and meiotic cell cycles in the C. elegans germ line.

scholarly journals Mutational Analysis of the Drosophila Sister-Chromatid Cohesion Protein ORD and Its Role in the Maintenance of Centromeric Cohesion

Genetics ◽  
1997 ◽  
Vol 146 (4) ◽  
pp. 1319-1331 ◽  
Author(s):  
Sharon E Bickel ◽  
Dudley W Wyman ◽  
Terry L Orr-Weaver
Keyword(s):  
Sister Chromatid ◽  
Mutational Analysis ◽  
Germ Line ◽  
Sister Chromatid Cohesion ◽  
Chromosome Loss ◽  
Male And Female ◽  
Chromatid Cohesion ◽  
Random Segregation ◽  
Kinetochore Function ◽  
Segregation Of Chromosomes

The ord gene is required for proper segregation of all chromosomes in both male and female Drosophila meiosis. Here we describe the isolation of a null ord allele and examine the consequences of ablating ord function. Cytologically, meiotic sister-chromatid cohesion is severely disrupted in flies lacking ORD protein. Moreover, the frequency of missegregation in genetic tests is consistent with random segregation of chromosomes through both meiotic divisions, suggesting that sister cohesion may be completely abolished. However, only a slight decrease in viability is observed for ord null flies, indicating that ORD function is not essential for cohesion during somatic mitosis. In addition, we do not observe perturbation of germ-line mitotic divisions in flies lacking ORD activity. Our analysis of weaker ord alleles suggests that ORD is required for proper centromeric cohesion after arm cohesion is released at the metaphase I/anaphase I transition. Finally, although meiotic cohesion is abolished in the ord null fly, chromosome loss is not appreciable. Therefore, ORD activity appears to promote centromeric cohesion during meiosis II but is not essential for kinetochore function during anaphase.

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