(n.) The formation of a bud in place of a fertilized ovule or oospore.
Example Sentences:
(1) It was concluded that they had developed by apogamy, and therefore did not require plasma membrane bound mating receptors, cell fusion, or zygote formation.
Parthenogenesis
Definition:
(n.) The production of new individuals from virgin females by means of ova which have the power of developing without the intervention of the male element; the production, without fertilization, of cells capable of germination. It is one of the phenomena of alternate generation. Cf. Heterogamy, and Metagenesis.
(n.) The production of seed without fertilization, believed to occur through the nonsexual formation of an embryo extraneous to the embrionic vesicle.
Example Sentences:
(1) O. puertoricensis did not exhibit autogeny or parthenogenesis.
(2) Cyclical parthenogenesis exaggerates the force of selection relative to recombination and will therefore enhance interlocus effects.
(3) Fertilization anomalies (possibly increased by in vitro procedures) were recorded: 1.6% of embryos resulted from parthenogenesis and 6.4% were polyploid (mainly polyspermic).
(4) Now, productive colonies of these lizards, which have remarkably little genetic variation, can be readily established and used not only for research on parthenogenesis but also for many kinds of experiments for which reptile systems are desirable.
(5) This rapid and extensive range expansion provides strong evidence that parthenogenesis can be a successful strategy for lizards in an environment with low and unpredictable rainfall.
(6) We used a comparison between cleavage rates and fertilization rates according to chromosomal analysis of oocytes to estimate the parthenogenesis frequency.
(7) These populations are thus panmictic, and most likely reproduce by cyclical parthenogenesis.
(8) Rickettsia-like maternally inherited bacteria have been shown to be involved in a variety of alterations of arthropod sexuality, such as female-biased sex ratios, parthenogenesis, and sterility of crosses either between infected males and uninfected females or between infected individuals (cytoplasmic incompatibility).
(9) There was no significant difference in parthenogenesis between any of the culture media and it appears to be a function of the strain of mice and the timing between human chorionic gonadotropin (hCG) injection and ovum collection.
(10) Parthenogenesis frequency was increased by male sexual rest.
(11) The causes for the variability of parthenogenesis indices in the polyploid clones are discussed.
(12) In vitro fertilization enabled the study of lethal (parthenogenesis) or sublethal (triploidy, monosomy and trisomy) chromosomal abnormalities in man.
(13) Methylamine appeared to activate oocytes, and most of them developed by haploid parthenogenesis.
(14) It is suggested that males are heteromorphic for the long homologue due to chromatin diminution, that occurs in the maturation division of mitotic parthenogenesis.
(15) A time-course experiment demonstrated that the extent of parthenogenetic activation in vivo following Br treatment was related to the period of time between drug injection and isolation of ova, the optimal period being 12 h. Neither Br nor MA had a direct activating effect on the oocytes as evidenced by an inability to induce parthenogenesis in vitro.
(16) Since calf thymocyte centrosomes do not support parthenogenesis, the present results suggest that duplication of the foreign centrosome is required for centrosome-induced parthenogenesis.
(17) The oocytes were prepared by a combined enzyme-mechanical method without impairing the fertility of the oocyte or inducing parthenogenesis.
(18) Comparisons are made with previously published models that deal with monogamous mating and with parthenogenesis.
(19) Parthenogenesis can only evolve in areas devoid of the generating bisexual species, because such species would prevent newly formed unisexuals from establishing clones due either to hybridization or competition.
(20) The evolutionary switch from paternal to maternal inheritance in mammals might be related to the additional dangers that parthenogenesis represents: a threat to the life of the mother as well as to the life of the fetus.