scholarly journals Maternal inheritance of mitochondria: implications for male fertility?

Reproduction ◽  
2018 ◽  
Vol 155 (4) ◽  
pp. R159-R168 ◽  
Author(s):  
R C Vaught ◽  
D K Dowling

Evolutionary theory predicts maternal inheritance of the mitochondria will lead to the accumulation of mutations in the mitochondrial DNA (mtDNA) that impair male fertility, but leave females unaffected. The hypothesis has been referred to as ‘Mother’s Curse’. There are many examples of mtDNA mutations or haplotypes, in humans and other metazoans, associated with decreases in sperm performance, but seemingly few reports of associations involving female reproductive traits; an observation that has been used to support the Mother’s Curse hypothesis. However, it is unclear whether apparent signatures of male bias in mitochondrial genetic effects on fertility reflect an underlying biological bias or a technical bias resulting from a lack of studies to have screened for female effects. Here, we conduct a systematic literature search of studies reporting mitochondrial genetic effects on fertility-related traits in gonochoristic metazoans (animals with two distinct sexes). Studies of female reproductive outcomes were sparse, reflecting a large technical sex bias across the literature. We were only able to make a valid assessment of sex specificity of mitochondrial genetic effects in 30% of cases. However, in most of these cases, the effects were male biased, including examples of male bias associated with mtDNA mutations in humans. These results are therefore consistent with the hypothesis that maternal inheritance has enriched mtDNA sequences with mutations that specifically impair male fertility. However, future research that redresses the technical imbalance in studies conducted per sex will be key to enabling researchers to fully assess the wider implications of the Mother’s Curse hypothesis to male reproductive biology.

2021 ◽  
Vol 12 ◽  
Author(s):  
Ziwei Chen ◽  
Luiz F. Brito ◽  
Hanpeng Luo ◽  
Rui Shi ◽  
Yao Chang ◽  
...  

Fertility and reproductive performance are key drivers of dairy farm profitability. Hence, reproduction traits have been included in a large majority of worldwide dairy cattle selection indexes. The reproductive traits are lowly heritable but can be improved through direct genetic selection. However, most scientific studies and dairy cattle breeding programs have focused solely on the genetic effects of the dam (GED) on reproductive performance and, therefore, ignored the contribution of the service sire in the phenotypic outcomes. This study aimed to investigate the service sire effects on female reproductive traits in Holstein cattle from a genomic perspective. Genetic parameter estimation and genome-wide association studies (GWAS) were performed for the genetic effect of service sire (GESS) on conception rate (CR), 56-day non-return rate (NRR56), calving ease (CE), stillbirth (SB), and gestation length (GL). Our findings indicate that the additive genetic effects of both sire and dam contribute to the phenotypic variance of reproductive traits measured in females (0.0196 vs. 0.0109, 0.0237 vs. 0.0133, 0.0040 vs. 0.0289, 0.0782 vs. 0.0083, and 0.1024 vs. 0.1020 for GESS and GED heritability estimates for CR, NRR56, CE, SB, and GL, respectively), and these two genetic effects are positively correlated for SB (0.1394) and GL (0.7871). Interestingly, the breeding values for GESS on insemination success traits (CR and NRR56) are unfavorably and significantly correlated with some production, health, and type breeding values (ranging from −0.449 to 0.274), while the GESS values on calving traits (CE, SB, and GL) are usually favorably associated with those traits (ranging from −0.493 to 0.313). One hundred sixty-two significant single-nucleotide polymorphisms (SNPs) and their surrounding protein-coding genes were identified as significantly associated with GESS and GED, respectively. Six genes overlapped between GESS and GED for calving traits and 10 genes overlapped between GESS for success traits and calving traits. Our findings indicate the importance of considering the GESS when genetically evaluating the female reproductive traits in Holstein cattle.


eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Maulik R Patel ◽  
Ganesh K Miriyala ◽  
Aimee J Littleton ◽  
Heiko Yang ◽  
Kien Trinh ◽  
...  

Due to their strict maternal inheritance in most animals and plants, mitochondrial genomes are predicted to accumulate mutations that are beneficial or neutral in females but harmful in males. Although a few male-harming mtDNA mutations have been identified, consistent with this ‘Mother’s Curse’, their effect on females has been largely unexplored. Here, we identify COIIG177S, a mtDNA hypomorph of cytochrome oxidase II, which specifically impairs male fertility due to defects in sperm development and function without impairing other male or female functions. COIIG177S represents one of the clearest examples of a ‘male-harming’ mtDNA mutation in animals and suggest that the hypomorphic mtDNA mutations like COIIG177S might specifically impair male gametogenesis. Intriguingly, some D. melanogaster nuclear genetic backgrounds can fully rescue COIIG177S -associated sterility, consistent with previously proposed models that nuclear genomes can regulate the phenotypic manifestation of mtDNA mutations.


2000 ◽  
Vol 70 (1) ◽  
pp. 9-16 ◽  
Author(s):  
A. Sewalem ◽  
K. Johansson

AbstractFertility, generally considered as a trait of the two parents, is perhaps best defined as the interaction between the male and female gametes in the production of a viable zygote. Although zygote development and hatchability are traits of the embryo influenced by maternal effects, in most previous studies they have been considered to be female reproductive traits. The aim of this work was to study the influence of sire on fertility and hatchability traits and to estimate the (co)variance components of direct and maternal genetic effects under a Bayesian setting via Gibbs sampling. We measured the fertility of 6396 eggs and the hatchability of 5393 embryos on an individual basis. In addition, egg weight from 42 to 63 weeks of age (EW63) was recorded on an individual egg basis. The sire accounted for a significant amount of the variation infertility and hatchability. For direct heritability, the marginal posterior mean, for fertility and hatchability were almost equal (0·24). The maternal heritabilities for fertility and hatchability were 0·20 and 0·18, respectively. The direct heritability value for the egg weight trait was high. The direct-direct genetic correlation between egg weight and hatchability was negative and significant. The genetic correlations between the direct effect of the egg weight trait and maternal effects for fertility and hatchability were low, with variable signs, and were not significant. On the other hand, significant negative genetic correlations between direct and maternal effects of fertility and hatchability were obtained (the posterior means were –0·56 for FE and –0·55 for HC).


2015 ◽  
Vol 64 (1-6) ◽  
pp. 91-99 ◽  
Author(s):  
R. Kamalakannan ◽  
M. Varghese ◽  
J.-M. Park ◽  
S.-H. Kwon ◽  
J.-H. Song ◽  
...  

Abstract Growth and reproductive traits were assessed in seed stands of two native Indian tree species Tamarindus indica and Azadirachta indica. Positive correlation between growth (height and GBH) and reproductive traits (male and female contribution) were found in both species. Fertility was estimated from the flower and fruit production of individuals. Based on the fertility variation among individuals, parental balance, femaleness index and status number (Ns) were determined. The option of equal seed collection among individuals was also considered for estimating Ns. The percentage of fertile trees was higher in the high flowering year in both species. The best male contributing individuals also showed high female contribution (fruit production). The parental contribution in seed stands showed high deviation from expectation; 20% individuals contributed about 70% of male and female gametes in both species. Femaleness index showed that female and male contribution of individual tree was more balanced in the good flowering year, compared to the poor year. Coefficient of variation in male and female fertility was higher in the low flowering year resulting in high fertility variation among individuals and low status number. In T. indica, the female contribution was less variable compared to that of male fertility whereas in A. indica the female fertility variation was higher than that of male fertility. The relative status number (Nr = Ns/N) of the stands was lower for male and female fertility compared to the combined (male and female) fertility of individual trees.


2004 ◽  
Vol 34 (4) ◽  
pp. 1163-1167 ◽  
Author(s):  
Luis Ernani Henkes ◽  
Magda Vieira Benavides ◽  
João Francisco Coelho Oliveira ◽  
José Carlos Ferrugem Moraes ◽  
Tania Azevedo Weimer

Cytoplasmic inheritance influence on reproductive traits was investigated in the Brangus-Ibagé cattle (3/8 Nelore x 5/8 Aberdeen Angus). Additive genetic effects were responsible for 12% ± 11% of phenotypic variation observed in first calving interval, but their contribution dropped to zero when all calving intervals (CI) were considered. The heritability estimate for age at first calving (AFC, in days) was 0.19 ± 0.09. Mitochondrial lineage (MIT) had negligible effects on phenotypic variances of calving interval (0.0 ± 0.02), calf birth weight (0.0 ± 0.01), and cow weight at calving (0.0 ± 0.01). However, for the age at first calving, MIT accounted for 0.15 ± 0.07 of total variation. Cow weight at calving had a significant linear effect on CI and AFC. Three D-loop mtDNA mutations significantly affected either calving interval (T®C at sites 16,113 and 16,119) or calf birth weight (T®C at site 16,113). The C variants had decreased CI (29 and 32 days, respectively) and increased calf weight (0.6kg). Although the effects were small, direct selection for these mutation-carrier cows might improve the reproductive and developmental performance in this herd.


Author(s):  
Yufeng Qian

The purpose of this chapter is to identify the potential and challenges in science education in the use of 3D MUVE science programs. These programs offer a number of instructional benefits in motivating and engaging students and in improving their science learning and scientific inquiry. 3D MUVE is a promising media in narrowing gender and racial achievement gaps and enabling an authentic and valid assessment of science education. Like all new instructional technologies, however, the wide use and implementation of 3D MUVE technology in mainstream science classroom is still facing a number of challenges, which are mainly related to technological complexity and cost, and design difficulty in incorporating some elements critical to inquiry-based learning into the 3D MUVE environment. To overcome these identified challenges and make optimal use of the opportunities, suggestions for integrating 3D MUVE into science curriculum and classroom are made and discussed, along with future research directions.


2015 ◽  
pp. 841-863
Author(s):  
Yufeng Qian

The purpose of this chapter is to identify the potential and challenges in science education in the use of 3D MUVE science programs. These programs offer a number of instructional benefits in motivating and engaging students and in improving their science learning and scientific inquiry. 3D MUVE is a promising media in narrowing gender and racial achievement gaps and enabling an authentic and valid assessment of science education. Like all new instructional technologies, however, the wide use and implementation of 3D MUVE technology in mainstream science classroom is still facing a number of challenges, which are mainly related to technological complexity and cost, and design difficulty in incorporating some elements critical to inquiry-based learning into the 3D MUVE environment. To overcome these identified challenges and make optimal use of the opportunities, suggestions for integrating 3D MUVE into science curriculum and classroom are made and discussed, along with future research directions.


2020 ◽  
Vol 35 (2) ◽  
pp. 377-393 ◽  
Author(s):  
Sally Mortlock ◽  
Raden I Kendarsari ◽  
Jenny N Fung ◽  
Greg Gibson ◽  
Fei Yang ◽  
...  

Abstract STUDY QUESTION Are genetic effects on endometrial gene expression tissue specific and/or associated with reproductive traits and diseases? SUMMARY ANSWER Analyses of RNA-sequence data and individual genotype data from the endometrium identified novel and disease associated, genetic mechanisms regulating gene expression in the endometrium and showed evidence that these mechanisms are shared across biologically similar tissues. WHAT IS KNOWN ALREADY The endometrium is a complex tissue vital for female reproduction and is a hypothesized source of cells initiating endometriosis. Understanding genetic regulation specific to, and shared between, tissue types can aid the identification of genes involved in complex genetic diseases. STUDY DESIGN, SIZE, DURATION RNA-sequence and genotype data from 206 individuals was analysed and results were compared with large publicly available datasets. PARTICIPANTS/MATERIALS, SETTING, METHODS RNA-sequencing and genotype data from 206 endometrial samples was used to identify the influence of genetic variants on gene expression, via expression quantitative trait loci (eQTL) analysis and to compare these endometrial eQTLs with those in other tissues. To investigate the association between endometrial gene expression regulation and reproductive traits and diseases, we conducted a tissue enrichment analysis, transcriptome-wide association study (TWAS) and summary data-based Mendelian randomisation (SMR) analyses. Transcriptomic data was used to test differential gene expression between women with and without endometriosis. MAIN RESULTS AND THE ROLE OF CHANCE A tissue enrichment analysis with endometriosis genome-wide association study summary statistics showed that genes surrounding endometriosis risk loci were significantly enriched in reproductive tissues. A total of 444 sentinel cis-eQTLs (P < 2.57 × 10−9) and 30 trans-eQTLs (P < 4.65 × 10−13) were detected, including 327 novel cis-eQTLs in endometrium. A large proportion (85%) of endometrial eQTLs are present in other tissues. Genetic effects on endometrial gene expression were highly correlated with the genetic effects on reproductive (e.g. uterus, ovary) and digestive tissues (e.g. salivary gland, stomach), supporting a shared genetic regulation of gene expression in biologically similar tissues. The TWAS analysis indicated that gene expression at 39 loci is associated with endometriosis, including five known endometriosis risk loci. SMR analyses identified potential target genes pleiotropically or causally associated with reproductive traits and diseases including endometriosis. However, without taking account of genetic variants, a direct comparison between women with and without endometriosis showed no significant difference in endometrial gene expression. LARGE SCALE DATA The eQTL dataset generated in this study is available at http://reproductivegenomics.com.au/shiny/endo_eqtl_rna/. Additional datasets supporting the conclusions of this article are included within the article and the supplementary information files, or are available on reasonable request. LIMITATIONS, REASONS FOR CAUTION Data are derived from fresh tissue samples and expression levels are an average of expression from different cell types within the endometrium. Subtle cell-specifc expression changes may not be detected and differences in cell composition between samples and across the menstrual cycle will contribute to sample variability. Power to detect tissue specific eQTLs and differences between women with and without endometriosis was limited by the sample size in this study. The statistical approaches used in this study identify the likely gene targets for specific genetic risk factors, but not the functional mechanism by which changes in gene expression may influence disease risk. WIDER IMPLICATIONS OF THE FINDINGS Our results identify novel genetic variants that regulate gene expression in endometrium and the majority of these are shared across tissues. This allows analysis with large publicly available datasets to identify targets for female reproductive traits and diseases. Much larger studies will be required to identify genetic regulation of gene expression that will be specific to endometrium. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by the National Health and Medical Research Council (NHMRC) under project grants GNT1026033, GNT1049472, GNT1046880, GNT1050208, GNT1105321, GNT1083405 and GNT1107258. G.W.M is supported by a NHMRC Fellowship (GNT1078399). J.Y is supported by an ARC Fellowship (FT180100186). There are no competing interests.


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