A sweeping chronicle of women's battles for reproductive freedom throughout American history, Pregnancy and Power explores the many forces--social, racial, economic, and political--that have shaped ...women's reproductive lives in the United States. Leading historian Rickie Solinger argues that a woman's control over her body involves much more than the right to choose an abortion. Reproductive politics were at play when slaveholders devised breeding schemes, when the U.S. government took Indian children from their families in the nineteenth century, and when doctors pressed Latina women to be sterilized in the 1970s. Tracing the diverse plot lines of women's reproductive lives throughout American history, Solinger redefines the idea of reproductive freedom, putting race and class at the center of the effort to control sex and pregnancy in America over time. Solinger asks which women have how many children under what circumstances, and shows how reproductive experiences have been encouraged or coerced, rewarded or punished, honored or exploited over the last 250 years. Viewed in this way, the debate over reproductive rights raises questions about access to sex education and prenatal care, about housing laws, about access to citizenship, and about which women lose children to adoption and foster care. Pregnancy and Power shows that a complete understanding of reproductive politics must take into account the many players shaping public policy-- lawmakers, educators, employers, clergy, physicians--as well as the consequences for women who obey and resist these policies. Tracing the diverse plotlines of women's reproductive lives throughout American history, Solinger redefines the idea of reproductive freedom, putting race and class at the center of the struggle to control sex and pregnancy in America.
Welcomed as liberation and dismissed as exploitation, egg freezing (oocyte cryopreservation) has rapidly become one of the most widely-discussed and influential new reproductive technologies of this ...century. In Freezing Fertility, Lucy van de Wiel takes us inside the world of fertility preservation—with its egg freezing parties, contested age limits, proactive anticipations and equity investments—and shows how the popularization of egg freezing has profound consequences for the way in which female fertility and reproductive aging are understood, commercialized and politicized. Beyond an individual reproductive choice for people who may want to have children later in life, Freezing Fertility explores how the rise of egg freezing also reveals broader cultural, political and economic negotiations about reproductive politics, gender inequities, age normativities and the financialization of healthcare. Van de Wiel investigates these issues by analyzing a wide range of sources—varying from sparkly online platforms to heart-breaking court cases and intimate autobiographical accounts—that are emblematic of each stage of the egg freezing procedure. By following the egg’s journey, Freezing Fertility examines how contemporary egg freezing practices both reflect broader social, regulatory and economic power asymmetries and repoliticize fertility and aging in ways that affect the public at large. In doing so, the book explores how the possibility of egg freezing shifts our relation to the beginning and end of life.
The emergence of apomixis-the transition from sexual to asexual reproduction-is a prominent feature of modern citrus. Here we de novo sequenced and comprehensively studied the genomes of four ...representative citrus species. Additionally, we sequenced 100 accessions of primitive, wild and cultivated citrus. Comparative population analysis suggested that genomic regions harboring energy- and reproduction-associated genes are probably under selection in cultivated citrus. We also narrowed the genetic locus responsible for citrus polyembryony, a form of apomixis, to an 80-kb region containing 11 candidate genes. One of these, CitRWP, is expressed at higher levels in ovules of polyembryonic cultivars. We found a miniature inverted-repeat transposable element insertion in the promoter region of CitRWP that cosegregated with polyembryony. This study provides new insights into citrus apomixis and constitutes a promising resource for the mining of agriculturally important genes.
The molecular pathways that trigger the initiation of embryogenesis after fertilization in flowering plants, and prevent its occurrence without fertilization, are not well understood
. Here we show ...in rice (Oryza sativa) that BABY BOOM1 (BBM1), a member of the AP2 family
of transcription factors that is expressed in sperm cells, has a key role in this process. Ectopic expression of BBM1 in the egg cell is sufficient for parthenogenesis, which indicates that a single wild-type gene can bypass the fertilization checkpoint in the female gamete. Zygotic expression of BBM1 is initially specific to the male allele but is subsequently biparental, and this is consistent with its observed auto-activation. Triple knockout of the genes BBM1, BBM2 and BBM3 causes embryo arrest and abortion, which are fully rescued by male-transmitted BBM1. These findings suggest that the requirement for fertilization in embryogenesis is mediated by male-genome transmission of pluripotency factors. When genome editing to substitute mitosis for meiosis (MiMe)
is combined with the expression of BBM1 in the egg cell, clonal progeny can be obtained that retain genome-wide parental heterozygosity. The synthetic asexual-propagation trait is heritable through multiple generations of clones. Hybrid crops provide increased yields that cannot be maintained by their progeny owing to genetic segregation. This work establishes the feasibility of asexual reproduction in crops, and could enable the maintenance of hybrids clonally through seed propagation
.
What determines the number and size of the seeds produced by a plant? How
often should it reproduce them? How often should a plant produce them? Why and how are seeds dispersed, and what are the ...implications for the diversity and composition of vegetation? These are just some of the questions tackled in this wide-ranging review of the role of seeds in the ecology of plants. The authors bring together information on the ecological aspects of seed biology, starting with a consideration of reproductive strategies in seed plants and progressing through the life cycle, covering seed maturation, dispersal, storage in the soil, dormancy, germination, seedling establishment, and regeneration in the field. The text encompasses a wide range of concepts of general relevance to plant ecology, reflecting the central role that the study of seed ecology has played in elucidating many fundamental aspects of plant community function.
Abstract
The present study evaluated the growth and puberty attainment of Bos indicus heifers administered recombinant bovine somatotropin (bST) or saline injections during preweaning and/or ...postweaning. On day 0, 177 suckling Nellore heifers were stratified by initial age and body weight (BW) (80 ± 10 d; 97 ± 16 kg), and randomly assigned, in a 2 × 2 factorial design (n = 44 to 45 heifers/treatment), to receive s.c. injections of saline (5 mL 0.9% NaCl) or sometribove zinc (Posilac; Elanco, Greenfield, IN; 6.14 mg/kg of BW0.75) on days 0 and 10 (PRE) and/or days 167 and 177 (POS). All heifers were managed as a single group in Brachiaria decumbens pastures from day 0 until 24 d postweaning (day 191), and then provided a corn silage–based TMR from days 191 to 380 to achieve 65% to 70% of mature BW at the end of the study (day 380). Heifer full BW was collected on days 0, 10, 167, 177, and monthly from days 191 to 380. Transrectal ultrasonography of ovaries was performed on days 1 and 10 of each month from days 229 to 380 to assess the percentage of pubertal heifers. Liver biopsies and blood samples from jugular vein were collected on days 0, 10, 167, 177, and 380. Additional blood samples were collected monthly from days 259 to 380 (n = 10 to 15 heifers/treatment). No interactions among day of the study, PRE, and POS injections of saline or bST were detected (P ≥ 0.11). Preweaning bST injections increased heifer average daily gain (ADG) from days 0 to 10 and plasma IGF-1 on day 10 (P ≤ 0.03), did not affect ADG from days 0 to 177, plasma IGF-1 from days 259 to 380, and any liver gene mRNA expression (P ≥ 0.19), but tended to decrease ADG from days 191 to 380 (P = 0.07) and percentage of pubertal heifers on days 349 (P = 0.07), 359 (P = 0.002), and 380 (P = 0.0001) compared with saline injections. Postweaning bST injections increased plasma IGF-1 on day 177 and overall liver mRNA expression of GHR-1A (P ≤ 0.05), decreased plasma IGF-1 from days 259 to 380 (P = 0.03), tended to decrease liver mRNA expression of GHR-1B on day 177 (P = 0.08), but did not affect ADG from days 167 to 177 and 191 to 380, and puberty attainment from days 229 to 380 (P ≥ 0.12) compared with saline injections. Thus, preweaning and postweaning injections of bST successfully increased heifer plasma IGF-1 concentrations 10 d after first injection. Postweaning injections of bST had no impact on puberty attainment, whereas preweaning bST injections of bST impaired puberty attainment of Nellore beef heifers.
Abstract
The objective of this long-term study was to improve the out-of-season breeding rates for ewes by examining effectiveness of dose levels of PG600, a combination of 80-IU/mL pregnant mare ...serum gonadotropin and 40-IU/mL human chorionic gonadotropin. Each week, during the anestrous season from 1998 through 2016, mature ewes were inserted with 1 of 2 progestogen devices. After 9 to 13 d, at removal of the device, ewes were injected intramuscularly with a specific dose of PG600. A total of 1,402 ewes were treated in this study, with weekly treatment groups ranging from 3 to 12 ewes. Ewes were assigned randomly in equal numbers to 1 of 2 ram pens with one fertile ram in each pen. Rams were fitted with a marking harness. Between 36 and 48 h after removal of the device, rams were switched. Ewes were checked for crayon marks (indicative of estrus) at 36, 48, and 96 h after removal of synchronizing devices. Rams were removed after 1 wk. Pregnancy status was diagnosed at 90 d of gestation using radiography and verified at 120 d or at lambing. To explore the impact of dose level, daylight, and temperature on pregnancy rate, we formulated an ordered multinomial probit model. The model controls statistically for dose level, synchronization device type, device reuse, and natural variation in minimum daily temperature and day of the year (DOY). Predicted pregnancy rate and type of birth at 90 d of gestation were significantly affected by DOY and temperature as well as dose level. Both observed and predicted pregnancy rates were higher for PG600 dose levels between 2.00 and 3.50 mL than for those below 2.00 mL or above 3.99 mL. By giving optimal amounts of PG600 to anestrous ewes, producers will have a greater number of pregnant ewes at lambing during the out-of-season lambing time.
lncRNAs in Plant and Animal Sexual Reproduction Golicz, Agnieszka A.; Bhalla, Prem L.; Singh, Mohan B.
Trends in plant science,
March 2018, 2018-03-00, 20180301, Letnik:
23, Številka:
3
Journal Article
Recenzirano
Long noncoding RNAs (lncRNAs) are transcripts over 200 base pairs in length with no discernible protein-coding potential. Multiple lines of evidence point to lncRNAs as master regulators, controlling ...the expression of protein-coding genes. Studies in plants and animals consistently show high expression of lncRNAs in reproductive organs in a cell- and tissue-specific manner. Sexual reproduction is a complex process that involves cell fate specification and specialized cell division requiring precise coordination of gene expression in response to intrinsic and extrinsic signals. The roles of lncRNAs as master regulators of gene expression and chromatin organization might make them particularly suited for coordination and control of molecular processes involved in sexual reproduction.
lncRNAs are molecules over 200 base pairs in length that do not code for proteins.
High levels of expression of lncRNAs in reproductive organs of both plants and animals have been observed.
Sexual reproduction requires cell fate specification and involves epigenetic changes, while lncRNAs are known to be involved in cell differentiation and have the ability to alter chromatin states.
Thus, lncRNAs can be particularly suited for fulfilment of roles in sexual reproduction in both plants and animals.
Almost all eukaryotes undergo sexual reproduction to generate diversity and select for fitness in their population pools. Interestingly, the systems by which sex is defined are highly diverse and can ...even differ between evolutionarily closely related species. While the most commonly known form of sex determination involves males and females in animals, eukaryotic microbes can have as many as thousands of different mating types for the same species. Furthermore, some species have found alternatives to sexual reproduction and prefer to grow clonally and yet undergo infrequent facultative sexual reproduction. These organisms are mainly invertebrates and microbes, but several examples are also present among vertebrates suggesting that alternative modes of sexual reproduction evolved multiple times throughout evolution. In this review, we summarize the sex-determination modes and variants of sexual reproduction found across the eukaryotic tree of life and suggest that eukaryotic microbes provide unique opportunities to study these processes in detail. We propose that understanding variations in modes of sexual reproduction can serve as a foundation to study the evolution of sex and why and how it evolved in the first place.
Today all politics are reproductive politics, argues esteemed feminist critic Laura Briggs. From longer work hours to the election of Donald Trump, our current political crisis is above all about ...reproduction. Households are where we face our economic realities as social safety nets get cut and wages decline. Briggs brilliantly outlines how politicians' racist accounts of reproduction-stories of Black "welfare queens" and Latina "breeding machines"-were the leading wedge in the government and business disinvestment in families. With decreasing wages, rising McJobs, and no resources for family care, our households have grown ever more precarious over the past forty years in sharply race-and class-stratified ways. This crisis, argues Briggs, fuels all others-from immigration to gay marriage, anti-feminism to the rise of the Tea Party.
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