Interests, Obligations, and Rights in Gamete and Embryo Donation: an Ethics Committee Opinion

Total Page:16

File Type:pdf, Size:1020Kb

Interests, Obligations, and Rights in Gamete and Embryo Donation: an Ethics Committee Opinion Interests, obligations, and rights in gamete and embryo donation: an Ethics Committee opinion Ethics Committee of the American Society for Reproductive Medicine American Society for Reproductive Medicine, Birmingham, Alabama This Ethics Committee report outlines the interests, obligations, and rights of all parties involved in gamete and embryo donation: both males and females who choose to provide gametes or embryos for use by others, recipients of donated gametes and embryos, individuals born as a result of gamete or embryo donation, and the programs that provide donated gametes and embryos to patients. This document replaces the document ‘‘Interests, obligations, and rights of the donor in gamete donation,’’ last published in 2014. (Fertil SterilÒ 2019;111:664–70. Ó2019 by American Society for Reproductive Medicine.) Earn online CME credit related to this document at www.asrm.org/elearn Discuss: You can discuss this article with its authors and other readers at https://www.fertstertdialog.com/users/16110-fertility- and-sterility/posts/42817-27610 KEY POINTS embryos once procured unless a since laws or individual circum- valid contract between the parties stances change and that there is a Programs should inform gamete do- provides otherwise. possibility they may be contacted nors and individuals donating em- Individuals should be informed that by offspring in the future. Similarly, bryos, as well as recipients of donor donating gametes or embryos does maintaining anonymity of parties gametes and donated embryos, about not give them legal rights or duties cannot be guaranteed since commer- potential legal, medical, and psycho- to rear any resulting children. Recip- cially available genetic testing social issues involved in their ients should be informed that upon and agencies that allow dissemina- donation. procurement of gametes or embryos, tion of identifying information Programs should inform donors and they assume legal rights and duties through social media increases the recipients that they may be screened over the gametes, embryos, and any risk of inadvertent disclosure of fi for speci c infectious diseases and resulting children produced from participants. other health-related risk factors, the donation. Programs should strongly encourage including genetic testing, and pro- Programs should consider that do- donors and recipients to provide the vide them with the results of such nors may have interests in learning program with medical updates if fi testing, inform them of the signi - the outcome of their donation, they learn of serious genetic or other cance of any medical conditions including whether any children conditions that are pertinent to the that are discovered, and offer donors have resulted from their participa- health of individuals sharing genetic and recipients referral if further tion. Programs should clearly inform relationships or might be significant counseling or medical care is donors and recipients before initi- to the health of a donor's future warranted. ating care, what, if any, information children. Donors should be given clear will be shared; this preference should Programs are strongly encouraged notice that although they may be documented. to develop and make available writ- withdraw from the donation Programs should caution partici- ten policies setting out the mecha- process at any point, they no pants that policies related to infor- nisms for collecting medical longer have dispositional control mation sharing are not guaranteed updates from donors and recipients, over their donated gametes or and, if applicable, for making avail- able or distributing newly acquired Received January 9, 2019; accepted January 10, 2019. medical information to individuals Correspondence: Ethics Committee, American Society for Reproductive Medicine, 1209 Montgomery Highway, Birmingham, Alabama 35216 (E-mail: [email protected]). whose health may be impacted by this information. Fertility and Sterility® Vol. 111, No. 4, April 2019 0015-0282/$36.00 Donors, recipients, and programs Copyright ©2019 American Society for Reproductive Medicine, Published by Elsevier Inc. https://doi.org/10.1016/j.fertnstert.2019.01.018 must recognize that they have a 664 VOL. 111 NO. 4 / APRIL 2019 Fertility and Sterility® unique and ongoing moral relationship with each other, their genetic and ancestral origins and in being able to act on and this obligation does not end with the procurement of that information. Donors have an interest in being able to gametes or the donation of embryos. Evolving medical donate, being protected in the process, being treated fairly if technology, laws, and social standards will likely require injuries occur, and not having obligations imposed on them reevaluation of these relationships throughout the lifetimes without their consent. They also may have an interest in hav- of the parties involved. ing contact with individuals born as a result of their donation. Contact between donors and individuals born as a result The use of sperm and egg donors in reproductive medi- of their donation has become an issue of special importance, cine, as well as the donation of embryos from individuals with many websites offering assistance to donor-conceived who themselves were enrolled in assisted reproduction, is people wishing to trace their genetic origins. This develop- now firmly established practice. As a result, concerns ment raises the possibility of unexpected contact between do- regarding the ability to share information related to the ge- nors and persons conceived from donated gametes or netic, health, and ancestral past history of the donors have embryos, as well as between other unknown genetically arisen. Less attention, however, has been given to the interests related parties that may be unaware of a donor's participation of the donors themselves, such as privacy, information about (for example, children of gamete and embryo donors who medical or genetic conditions discovered through screening share a genetic link). Moreover, heightened sensitivity to or subsequent medical care if injuries occur as a result of the interests of individuals born as a result of donation in donation, selection of recipients, knowledge of outcome knowing their genetic and ancestral histories suggests that from pregnancies resulting from their donated gametes and donors may bear some responsibility in the donation process embryos, disclosure of adverse pregnancy outcome events, to facilitate the provision of accurate information about pedi- and contact or noncontact with individuals born as a result gree and their family health history. The interest of individ- of their participation. uals knowing their origins, however, neither requires The term ‘‘donor’’ has been used conventionally for de- knowledge of the specific identity of the donor nor extends cades to describe an individual who provides gametes (eggs to contact with the donor. It is also unclear to what extent do- or sperm) that have been manipulated outside the human nors must go in providing updates about their health informa- body with the intent of producing a pregnancy in a recipient. tion for the benefit of recipients or genetically related Typically, gamete donors do not intend to establish a legal individuals. However, increased public attention to this issue relationship (that is, no parental rights or responsibilities) suggests the presence of evolving responsibilities for persons with any resulting child. The present statement focuses on to consider before donating gametes or embryos to enable matters that affect both egg and sperm donors, as well as in- others to have children. dividuals who donate embryos to programs for reproductive Before gamete or embryo donation occurs, informed con- purposes. Important issues include updates about medical his- sent requires donors to be honest about their family and per- tory and the possibility of later contact between participants. sonal health histories, and their personal behaviors, to Differences will be taken into account where relevant in the ascertain genetic and health risks that could affect the well- discussion. being of genetically related individuals. Less clear is the The involved parties in gamete donation and embryo extent to which, after donation, donors have ongoing respon- donation are the donors,therecipients or intended parents, sibilities to keep programs or recipients informed of their and the individuals born as a result of the donation. These health status or disclose any new medical findings that might parties have distinct but, at times, competing interests. be of interest to parents to protect the health of children born These interests may give rise to rights and corresponding from donation. obligations. At present, there is little consensus about Another area of uncertainty relates to the independent in- how to balance conflicting interests or define the rights terests that donors may have in the treatment process and its and responsibilities of donors, recipients, and programs. outcomes. Whereas some donors may be content with simply For this reason, it is especially important that programs providing their gametes or embryos, others may be interested are explicit about expectations regarding future informa- in knowing more personal information about the recipients or tion sharing and contact between donors and individuals the outcome of their donation, including any complications born as a result of donation. that may arise (1). These interests may conflict with the inter- Recipients
Recommended publications
  • THE PHYSIOLOGY and ECOPHYSIOLOGY of EJACULATION Tropical and Subtropical Agroecosystems, Vol
    Tropical and Subtropical Agroecosystems E-ISSN: 1870-0462 [email protected] Universidad Autónoma de Yucatán México Lucio, R. A.; Cruz, Y.; Pichardo, A. I.; Fuentes-Morales, M. R.; Fuentes-Farias, A.L.; Molina-Cerón, M. L.; Gutiérrez-Ospina, G. THE PHYSIOLOGY AND ECOPHYSIOLOGY OF EJACULATION Tropical and Subtropical Agroecosystems, vol. 15, núm. 1, 2012, pp. S113-S127 Universidad Autónoma de Yucatán Mérida, Yucatán, México Available in: http://www.redalyc.org/articulo.oa?id=93924484010 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Tropical and Subtropical Agroecosystems, 15 (2012) SUP 1: S113 – S127 REVIEW [REVISIÓN] THE PHYSIOLOGY AND ECOPHYSIOLOGY OF EJACULATION [FISIOLOGÍA Y ECOFISIOLOGÍA DE LA EYACULACIÓN] R. A. Lucio1*, Y. Cruz1, A. I. Pichardo2, M. R. Fuentes-Morales1, A.L. Fuentes-Farias3, M. L. Molina-Cerón2 and G. Gutiérrez-Ospina2 1Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala-Puebla km 1.5 s/n, Loma Xicotencatl, 90062, Tlaxcala, Tlax., México. 2Depto. Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, México, D.F., México. 3Laboratorio de Ecofisiologia Animal, Departamento de Fisiologia, Instituto de Investigaciones sobre los Recursos Naturales, Universidad Michoacana de San Nicolás de Hidalgo, Av. San Juanito Itzicuaro s/n, Colonia Nueva Esperanza 58337, Morelia, Mich., México * Corresponding author ABSTRACT RESUMEN Different studies dealing with ejaculation view this Diferentes estudios enfocados en la eyaculación, process as a part of the male copulatory behavior.
    [Show full text]
  • Female and Male Gametogenesis 3 Nina Desai , Jennifer Ludgin , Rakesh Sharma , Raj Kumar Anirudh , and Ashok Agarwal
    Female and Male Gametogenesis 3 Nina Desai , Jennifer Ludgin , Rakesh Sharma , Raj Kumar Anirudh , and Ashok Agarwal intimately part of the endocrine responsibility of the ovary. Introduction If there are no gametes, then hormone production is drastically curtailed. Depletion of oocytes implies depletion of the major Oogenesis is an area that has long been of interest in medicine, hormones of the ovary. In the male this is not the case. as well as biology, economics, sociology, and public policy. Androgen production will proceed normally without a single Almost four centuries ago, the English physician William spermatozoa in the testes. Harvey (1578–1657) wrote ex ovo omnia —“all that is alive This chapter presents basic aspects of human ovarian comes from the egg.” follicle growth, oogenesis, and some of the regulatory mech- During a women’s reproductive life span only 300–400 of anisms involved [ 1 ] , as well as some of the basic structural the nearly 1–2 million oocytes present in her ovaries at birth morphology of the testes and the process of development to are ovulated. The process of oogenesis begins with migra- obtain mature spermatozoa. tory primordial germ cells (PGCs). It results in the produc- tion of meiotically competent oocytes containing the correct genetic material, proteins, mRNA transcripts, and organ- Structure of the Ovary elles that are necessary to create a viable embryo. This is a tightly controlled process involving not only ovarian para- The ovary, which contains the germ cells, is the main repro- crine factors but also signaling from gonadotropins secreted ductive organ in the female.
    [Show full text]
  • The Human Reproductive System
    ANATOMY- PHYSIOLOGY-REPRODUCTIVE SYSTEM - IN RESPONSE TO CONVID 19 APRIL 2, 2020 nd Dear students and parents, April 2 , 2020 Beginning two days prior to our last day at school I issued work packets to all students in all classed; the content of which was spanning a two-three week period. Now that our removal from school will continue to at least May 1st, I have provided the following work packets which will span the remainder of the year, should our crisis continue. The following folders are available: ANATOMY – PHYSIOLOGY 1. Packet – THE HUMAN REPRODUCATIVE AND ENDOCRINE SYSTEMS. 2. Packet- THE HUMAN NERVOUS SYSTEM 3. Packet handed our prior to our last day: THE HUMAN EXCRETORY SYSTEM ZOOLOGY 1. Packet- STUDY OF THE CRUSTACEANS 2. Packet- STUDY OF THE INSECTS 3. Packet- handed our prior to our last day- INTRODUCTION TO THE ARTRHROPODS- CLASSES MYRIAPODA AND ARACHNIDA AP BIOLOGY – as per the newly devised topics of study focus, structure of adapted test, test dates and supports provided as per the guidelines and policies of The College Board TO ALL STUDENTS! THESE PACKETS WILL BE GUIDED BY THE SAME PROCEDURES WE EMBRACED DURING FALL TECH WEEK WHERE YOU ARE RESPONSIBLE FOR THE WORK IN THE PACKETS- DELIVERED UPON YOUR RETURN TO SCHOOL OR AS PER UNFORESEEN CHANGES WHICH COME OUR WAY. COLLABORATION IS ENCOURAGED- SO STAY IN TOUCH AND DIG IN! YOUR PACKETS WILL BE A NOTEBOOK GRADE. EVENTUALLY YOU SHALL TAKE AN INDIVIDUAL TEST OF EACH PACKET = AN EXAM GRADE! SCHOOL IS OFF SITE BUT NOT SHUT DOWN SO PLEASE DO THE BODY OF WORK ASSIGNED IN THE PACKETS PROVIDED.
    [Show full text]
  • Oogenesis/Folliculogenesis Ovarian Follicle Endocrinology
    Oogenesis/Folliculogenesis & Ovarian Follicle Endocrinology follicle - composite structure Ovarian Follicle that will produce mature oocyte – primordial follicle - germ cell (oocyte) with a single layer ZP of mesodermal cells around it TI & TE it – as development of follicle progresses, oocyte will obtain a ‘‘halo’’ of cells and membranes that are distinct: Oocyte 1. zona pellucide (ZP) 2. granulosa (Gr) 3. theca interna and externa (TI & TE) Gr Summary: The follicle is the functional unit of the ovary. One female gamete, the oocyte is contained in each follicle. The granulosa cells produce hormones (estrogen and inhibin) that provide ‘status’ signals to the pituitary and brain about follicle development. Mammal - Embryonic Ovary Germ Cells Division and Follicle Formation from Makabe and van Blerkom, 2006 Oogenesis and Folliculogenesis GGrraaaafifiaann FFoolliclliclele SStrtruucctuturree SF-1 Two Cell Steroidogenesis • Common in mammalian ovarian follicle • Part of the steroid pathway in – Granulosa – Theca interna • Regulated by – Hypothalamo-pituitary axis – Paracrine factors blood ATP FSH LH ATP Estradiol-17β FSH-R LH-R mitochondrion cAMP cAMP CHOL P450arom PKA 17βHSD C P450scc PKA C C C cholesterol pool PREG Testosterone StAR 3βHSD Estrone SF-1 PROG 17βHSD P450arom Androstenedione nucleus Andro theca Mammals granulosa Activins & Inhibins Pituitary - Gonadal Regulation of the FSH Adult Ovary E2 Inhibin Activin Follistatin Inhibins and Activins •Transforming Growth Factor -β (TGF-β) family •Many gonadal cells produce β subunits •In
    [Show full text]
  • Formation of Gametes (Eggs & Sperm)
    Meiosis Formation of Gametes (Eggs & Sperm) 1 Facts About Meiosis ü 4 haploid daughter cells are produced (each contain half the number of chromosomes as the original cell) ü Produces gametes (eggs & sperm) ü Occurs in the testes in males (Spermatogenesis) ü Occurs in the ovaries in females (Oogenesis) 2 Meiosis: Two Part Cell Division Sister chromatids separate Homologous Chromosomes separate Meiosis Meiosis I II Diploid Diploid Haploid 3 Why Do we Need Meiosis? ü sexual reproduction ü two haploid (1n) gametes are brought together through fertilization to form a diploid (2n) zygote 4 Fertilization 2n = 6 1n =3 5 Meiosis I: Reduction Division Telophase I Late Prophase I Anaphase I (haploid) Metaphase I Nucleus Spindle fibers Early Prophase I Nuclear (Chromosome number doubled envelope because has gone through S phase of interphase) 6 Prophase I Early prophase Late prophase ü Homologs pair ü Chromosomes condense. through synapsis ü Spindle forms. forming tetrads. ü Nuclear envelope breaks ü Crossing over down. 7 occurs. Crossing-Over Crossing-over multiplies the already huge number of different gamete types produced by independent assortment 8 Metaphase I Homologous pairs of chromosomes align across from each other along the equator of the cell. Random alignment is called Independent Assortment. 9 Anaphase I Homologs separate and move to opposite poles. Sister chromatids remain attached at their centromeres. 10 Telophase I Nuclear envelopes reassemble. Spindle disappears. Cleavage furrow forms and cytokinesis divides cell into two. 11 Prophase II Nuclear envelope breaks down. Spindle forms. 12 Metaphase II Chromosomes align On the equator of cells. 13 Anaphase II Equator Pole Sister chromatids separate and move to opposite poles.
    [Show full text]
  • Gametogenesis and Fertilization
    Gametogenesis and Fertilization Barry Bean for BioS 90 & 95 12 September 2008 Life is short. Especially if you’re a sperm cell! Used with permission of the artist, Patrick Moberg Try to remember… when you were gametes ! Think like a sperm… Think like an oocyte… http://usuarios.lycos.es/biologiacelular1/Aparato%20reproductor%20 masculino8_archivos/532047.jpg “Mammalian Fertilization” R.Yanagimachi, 1994. Gametes are prefabricated for action, a cascade of functions. Gamete production includes unique patterns of gene expression and regulation. Gametes have complex structure and many phenotypes. Every Gamete is a genetically distinct human individual! Here’s where they came from… Your parents… Fig. 05-05 When fetuses… PGCs, Primordial Germ Cells populated the presumptive gonadal tissue… from Sylvia Mader, Human Reproductive Biology Gametogenesis from Sylvia Mader, Human Reproductive Biology, 3rd ed. Gametogenesis from Sylvia Mader, Human Reproductive Biology, 3rd ed. from Sylvia Mader, Human Fig. 01-09 Reproductive Biology, 3rd ed. From Alberts et al., Molecular Biology of the Cell, 5th ed., 2008 Consequence: Every product of meiosis is genetically distinct from every other one! from Sylvia Mader, Human Reproductive Biology 250 m 273 yds 0.16 miles From Alberts et al., Molecular Biology of the Cell, 5th ed., 2008 From: Rupert Amann, Journal of Andrology, Vol. 29, No. 5, September/October 2008 DSP = daily sperm production ~108/day From: Rupert Amann, Journal of Andrology, Vol. 29, No. 5, September/October 2008 from Sylvia Mader, Human Fig. 06-07 Reproductive Biology, 3rd ed. From Alberts et al., Molecular Biology of the Cell, 5th ed., 2008 Fertilization Green=Acrosome Purple=Zona Pelludica Gray= Sperm w/out Acrosome **note that the acrosome compartment opened after contact with the zona pellucida http://www.nature.com/fertility/content/images/ncb-nm-fertilitys57-f1.jpg http://www.cnuh.co.kr/kckang/FemaleReproductiveMedicine/images/fig2 5-003.png From Cell Mol Life Sci 64 (2007) Fig.
    [Show full text]
  • And Gamete-Specific Patterns of X Chromosome Segregation in a Three-Gendered Nematode
    bioRxiv preprint doi: https://doi.org/10.1101/205211; this version posted October 18, 2017. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC 4.0 International license. Gender- and gamete-specific patterns of X chromosome segregation in a three-gendered nematode Sophie Tandonnet1, Maureen C. Farrell2, Georgios D. Koutsovoulos3,4, Mark L. Blaxter3, Manish Parihar1, 5, Penny L. Sadler2, Diane C. Shakes2, Andre Pires-daSilva1* 1School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK 2Department of Biology, College of William and Mary, Williamsburg, VA 23187, USA 3Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3JT, UK 4Present address: INRA, UMR1355 Institute Sophia Agrobiotech, F-06903 Sophia Antipolis, France 5Present address: Departments of Molecular Medicine and Institute of Biotechnology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA. *Corresponding author Keywords Meiosis, lack of recombination, X chromosome, Auanema rhodensis, father-to-son X transmission, nematode, SB347 Highlights - Matings between A. rhodensis hermaphrodites and males generate only male cross- progeny. - Hermaphrodites generate mostly nullo-X oocytes and diplo-X sperm. - Following normal Mendelian genetics, XX females produce haplo-X oocytes. - In cross-progeny, sons always inherit the X chromosome from the father. 1 bioRxiv preprint doi: https://doi.org/10.1101/205211; this version posted October 18, 2017. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.
    [Show full text]
  • The Evolution of Male-Female Dimorphism: Older Than Sex?
    J. Genet. Vol. 69, No. 1, April 1990, pp. 11-15. 9 Printed in India. The evolution of male-female dimorphism: Older than sex? ROLF F. HOEKSTRA Department of Genetics, Agricultural University, Dreijenlaan 2, 6703 HA Wageningen, The Netherlands Abstract. This contribution considers the evolution of a dimorphism with respect to cell fusion characteristics in a population of primitive cells. These cells reproduce exclusively asexually. The evolution towards asymmetric fusion behaviour of cells is driven by selection promoting horizontal transfer of an endosymbiontic replicator. It is concluded that evolution of asymmetric cell fusion in this scenario is more likely than evolution of sexual differentiation in a sexually reproducing population. Pre-existing dimorphism with respect to cell fusion may thus have been the basis for the establishment of sexual differentiation at the level of gamete fusion, and this in turn is fundamental to the evolution of two different sexes, male and female. Keywords. Sexes; mating type; horizont;d transmission; evolution. 1. Introduction Sex is a composite phenomenon characterized by the succession of fusion, recombination, and division. Fusion, the bringing together of the hereditary material from two nuclei (which are generally derived from different individuals), is " effected by a preceding fusion of two specialized cells (gametes) which are, as far as we know, always of different types. In anisogamous species, where the gametes differ in size, the two types are denoted male and female; in isogamous species the two gamete types do not differ morphologically and are called mating types. This characteristic difference between the two gametes fusing to form a zygote is the basis for the sexual differentiation into males and females.
    [Show full text]
  • Introduction.-The Foundations Were Laid for a Quantitative Theory of Sex by the Brilliant Pioneer Work of Goldschmidt and Bridges
    VOL. 16, 1930 GENETICS: W. E. CASTLE 783 filled with sand and rubble of corals, shells and foraminifera. The same structure is revealed in cores from borings, such as those made at Funafuti. It is the biotic cementation by the nullipore which sets off the coral reef (or island) of Darwin and his successors from other calcareous reefs, and it is the nullipore, therefore, which controls and shapes the reef from its origin to its final form. Since cementing and even what may properly be called reef-forming nullipores may be the exclusive constituents of a so- called "coral reef," and since they are, as a group of organisms, exempt from the depth limitation of "reef-forming corals," the only observation of Dar- win's hypothesis (hardly a true theory) is eliminated; and his assumption of interconvertibility and the consequent assumption of subsidence during reef development are unnecessary. THE QUANTITATIVE THEORY OF SEX AND THE GENETIC CHARACTER OF HAPLOID MALES By W. E. CASTLE BUSSEY INSTITUTION, HARVAR UNIVERSITY Communicated November 4, 1930 Introduction.-The foundations were laid for a quantitative theory of sex by the brilliant pioneer work of Goldschmidt and Bridges. 1. Goldschmidt was led to formulate a quantitative theory of sex by his studies of the genetics of the gipsy moth. He found that when different geographical races were crossed, as for example European and Japanese, individuals of mixed sexual character were often produced which he termed intersexes. Sometimes these individuals were predominantly female, sometimes predominantly male; sometimes their change from the expected sex character was so complete as to amount to sex reversal and only uni- sexual broods were obtained, exclusively male or exclusively female.
    [Show full text]
  • Negatively Assorted Gamete Fertilization for Supernumerary Heterochromatin in Two Grasshopper Species
    Heredity 76 (1996) 651—657 Received 9 October 1995 Negatively assorted gamete fertilization for supernumerary heterochromatin in two grasshopper species M. D. LOPEZ-LEON, J. CABRERO & J. P. M. CAMACHO* Departamento de Genét/ca, Facu/tad de Ciencias, Universidad de Granada, E-18071 Granada, Spain Theanalysis of controlled crosses and gravid females in two grasshopper species has shown nonrandom gamete fertilization, caused in both cases by a preference for ova and sperm to fuse with gametes carrying an allele different from their own. Such a fertilization bias was observed for a B chromosome in Eyprepocnemis plorans and a supernumerary chromosome segment on the M7 autosome in Chorthippus jacobsi. In addition, a male-biased sex ratio was observed in E. plorans among the embryo offspring produced by lB gravid females which had mated with a lB male in the field, but no sex ratio distortion was apparent in the same type of crosses performed in the laboratory. The possible causes of these distortions, and the role which negatively assorted fertilization may play upon the maintenance of these polymorphisms in natural populations, are discussed. Keywords:Bchromosomes, grasshoppers, homogamy, Mendelian segregation, preferential fertilization. some of which could be relevant during fertilization, Introduction and whose variation could be the basis for nonran- Randomgamete fertilization is a general assumption domness of this process. for Mendelian inheritance, as random mating is for Supernumerary heterochromatin constitutes the the Hardy—Weinberg law. Exceptions to random most frequent chromosomal polymorphism in mating have been widely described and constitute natural populations of grasshoppers. It may appear the basis for sexual selection, as noted by Darwin in the form of additional heterochromatic chromo- (1871).
    [Show full text]
  • Reproductive Strategies and Sexual Dimorphism in Bryopsidales Marine Green Algae
    Evolutionary Ecology Research, 2006, 8: 617–628 Gamete behaviours and the evolution of ‘marked anisogamy’: reproductive strategies and sexual dimorphism in Bryopsidales marine green algae Tatsuya Togashi,1,4* Masaru Nagisa,2 Tatsuo Miyazaki,1 Jin Yoshimura,1,3 John L. Bartelt4 and Paul Alan Cox4 1Marine Biosystems Research Center, Chiba University, Chiba, Japan, 2Department of Mathematics and Informatics, Faculty of Science, Chiba University, Chiba, Japan, 3Department of Systems Engineering, Shizuoka University, Hamamatsu, Japan and 4Institute for Ethnobotany, National Tropical Botanical Garden, Kalaheo, HI, USA ABSTRACT Questions: In some species of markedly anisogamous marine green algae, why do male gametes alone have no phototactic device? Why do some of their partners (female gametes) have pheromonal attraction systems? Simulation methods: Three-dimensional swimming and fertilization model with parameters based on experimental data of gametic traits (gamete sizes, swimming speeds and trajectories) and pseudo-parallel algorithms compiled for rapid calculations with large numbers of gametes. Key assumptions: The biomass allocated to produce gametes is similar between mating types. Each spherical gamete swims three-dimensionally at a speed determined by its diameter. Swimming speed is inversely proportional to gamete size according to Stoke’s law. Results: Under conditions in which disturbance under water may be a consideration, ‘markedly anisogamous species’ have a greater chance of successful fertilization than species with phototactic gametes in both sexes. This is more conspicuous in species with larger female gametes or pheromonal attraction systems. However, in deeper water, species with non-phototactic gametes in both sexes generally have a numerical advantage in mating over species with phototactic gametes.
    [Show full text]
  • Appendix B Glossary of Terms
    2012Appendix B Glossary of Terms APPENDIX B: GLOSSARY OF TERMS Adverse outcome . A pregnancy that does not result Donor egg cycle . An embryo is formed from in a live birth. The adverse outcomes reported for the egg of one woman (the donor) and then ART procedures are miscarriages, induced abortions, transferred to another woman (the recipient). and stillbirths. The donor relinquishes all parental rights to any American Society for Reproductive Medicine resulting offspring. (ASRM) . Professional society whose affiliate Donor embryo . An embryo that is donated by a organization, the Society for Assisted Reproductive patient who previously underwent ART treatment Technology (SART), is composed of clinics and and had extra embryos available. programs that provide ART. Ectopic pregnancy . A pregnancy in which the ART (assisted reproductive technology) . All fertilized egg implants in a location outside of the treatments or procedures that involve surgically uterus—usually in the fallopian tube, the ovary, or removing eggs from a woman’s ovaries and the abdominal cavity. Ectopic pregnancy is a combining the eggs with sperm to help a woman dangerous condition that must receive prompt become pregnant. The types of ART are in vitro medical treatment. fertilization (IVF), gamete intrafallopian transfer Egg . A female reproductive cell, also called an (GIFT), and zygote intrafallopian transfer (ZIFT). oocyte or ovum. ART cycle . A process in which (1) an ART procedure Egg retrieval (also called oocyte retrieval) . A is performed, (2) a woman has undergone ovarian procedure to collect the eggs contained in the stimulation or monitoring with the intent of having ovarian follicles. an ART procedure, or (3) frozen embryos have been thawed with the intent of transferring them to a Egg transfer (also called oocyte transfer) .
    [Show full text]