College of Agriculture & Natural Resources
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The collections in this community comprise faculty research works, as well as graduate theses and dissertations.
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Item Inheritance Reform, Female Empowerment, and Intergenerational Effects: Theory and Evidence from India(2022) Ibnat, Fabliha; Leonard, Kenneth L.; Agricultural and Resource Economics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Land ownership is an important determinant of intra-household bargaining power in low-income countries, yet women are systematically barred from inheriting land. Granting equal access to land tenuring has the potential to improve women's ability to make decisions within the household, particularly regarding their children. This dissertation examines the effect of women’s land inheritance rights on fertility and child mortality in India. I explore this topic theoretically and empirically in three main chapters. In the first chapter I develop a household bargaining model in which granting mothers inheritance rights may affect child mortality and fertility through a direct land channel and an indirect human capital channel. The model shows how an exogenous change in inheritance rights decreases fertility and has an ambiguous effect on child mortality for some households due to two competing effects. One is an empowerment effect that results from an increase to women's bargaining power and reduces child mortality. The second is an income effect that increases child mortality and results from an increase in the pooled unearned income of the household. Which effect dominates is an empirical question. In the second chapter I empirically estimate the effect of the reforms as they operate through each channel using quasi-random variation from a natural experiment in which four Indian states enacted equal rights for women to inherit joint family property between 1986 and 1994. I construct difference-in-differences estimators using variation in eligibility across marriage cohorts and religions. Using retrospective life history and fertility history data, hazard model estimates show that the reforms reduced child mortality through the land channel and reduced fertility through the human capital channel. Children with eligible mothers have a 57% lower hazard of dying before age five. Eligible women are more likely to delay their first birth and have a 32% lower hazard of having more than two children. The results correspond to 344,169 children who were saved between the reform passage years and 2005, the survey collection year. In the third chapter I use a different dataset to identify the specific subset of households for which the theoretical model generates an ambiguous prediction. I directly test the prediction using an event study difference-in-differences model that exploits variation in eligibility across states and multiple pre- and post-reform marriage cohorts. I find that household level child mortality decreases by 2.2 percentage points, indicating that the empowerment effect dominates the income effect.Item DNA methylation profiles correlated to striped bass sperm fertility(Springer Nature, 2018-04-10) Woods, L. Curry III; Li, Yaokun; Ding, Yi; Liu, Jianan; Reading, Benjamin J.; Fuller, S. Adam; Song, JiuzhouStriped bass (Morone saxatilis) spermatozoa are used to fertilize in vitro the eggs of white bass (M. chrysops) to produce the preferred hybrid for the striped bass aquaculture industry. Currently, only one source of domestic striped bass juveniles is available to growers that is not obtained from wild-caught parents and is thus devoid of any genetic improvement in phenotypic traits of importance to aquaculture. Sperm epigenetic modification has been predicted to be associated with fertility, which could switch genes on and off without changing the DNA sequence itself. DNA methylation is one of the most common epigenetic modification types and changes in sperm epigenetics can be correlated to sub-fertility or infertility in male striped bass. The objective of this study was to find the differentially methylated regions (DMRs) between high-fertility and sub-fertility male striped bass, which could potentially regulate the fertility performance. In our present study, we performed DNA methylation analysis of high-fertility and sub-fertility striped bass spermatozoa through MBD-Seq methods. A total of 171 DMRs were discovered in striped bass sperm correlated to fertility. Based on the annotation of these DMRs, we conducted a functional classification analysis and two important groups of genes including the WDR3/UTP12 and GPCR families, were discovered to be related to fertility performance of striped bass. Proteins from the WDR3/UTP12 family are involved in forming the sperm flagella apparatus in vertebrates and GPCRs are involved in hormonal signaling and regulation of tissue development, proliferation and differentiation. Our results contribute insights into understanding the mechanism of fertility in striped bass, which will provide powerful tools to maximize reproductive efficiencies and to identify those males with superior gametes for this important aquaculture species.Item Genome changes due to artificial selection in U.S. Holstein cattle(Springer Nature, 2019-02-11) Ma, Li; Sonstegard, Tad S.; Cole, John B.; VanTassell, Curtis P.; Wiggans, George R.; Crooker, Brian A.; Tan, Cheng; Prakapenka, Dzianis; Liu, George E.; Da, YangThe availability of a unique unselected Holstein line since 1964 provided a direct comparison between selected and unselected Holstein genomes whereas large Holstein samples provided unprecedented statistical power for identifying high-confidence SNP effects. Utilizing these unique resources, we aimed to identify genome changes affected by selection since 1964.Item Bos taurus–indicus hybridization correlates with intralocus sexual-conflict effects of PRDM9 on male and female fertility in Holstein cattle(Springer Nature, 2019-08-28) Seroussi, Eyal; Shirak, Andrey; Gershoni, Moran; Ezra, Ephraim; Santos, Daniel Jordan de Abreu; Ma, Li; Liu, George E.Crossover localization during meiotic recombination is mediated by the fast-evolving zinc-finger (ZnF) domain of gene PRDM9. To study its impact on dairy cattle performance, we compared its genetic variation between the relatively small Israeli (IL) Holsteins and the North American (US) Holsteins that count millions.