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Sterility (physiology)
Sterility is the physiological inability to effect sexual reproduction in a living thing, members of whose kind have been produced sexually. Sterility has a wide range of causes. It may be an inherited trait, as in the mule; or it may be acquired from the environment, for example through physical injury or disease, or by exposure to radiation. Sterility is the inability to produce a biological child, while infertility is the inability to conceive after a certain period. Sterility is rarely discussed in clinical literature and is often used synonymously with infertility. Infertility affects about 12-15% of couples globally. Still, the prevalence of sterility remains unknown. Sterility can be divided into three subtypes natural, clinical, and hardship. Natural sterility is the couple's physiological inability to conceive a child. Clinical sterility is natural sterility for which treatment of the patient will not result in conception. Hardship sterility is the inability to take adv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physiological
Physiology (; ) is the science, scientific study of function (biology), functions and mechanism (biology), mechanisms in a life, living system. As a branches of science, subdiscipline of biology, physiology focuses on how organisms, organ systems, individual organ (biology), organs, cell (biology), cells, and biomolecules carry out chemistry, chemical and physics, physical functions in a living system. According to the classes of organisms, the field can be divided into clinical physiology, medical physiology, Zoology#Physiology, animal physiology, plant physiology, cell physiology, and comparative physiology. Central to physiological functioning are biophysics, biophysical and biochemical processes, homeostasis, homeostatic control mechanisms, and cell signaling, communication between cells. ''Physiological state'' is the condition of normal function. In contrast, ''pathology, pathological state'' refers to abnormality (behavior), abnormal conditions, including human diseases. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
XX Male Syndrome
XX male syndrome, also known as de la Chapelle syndrome or 46,XX testicular disorder of sex development (or 46,XX DSD) is a rare intersex condition in which an individual with a 46,XX karyotype develops a male phenotype.updated 2015 In 90 percent of these individuals, the syndrome is caused by the Y chromosome's '' SRY'' gene, which triggers male reproductive development, being atypically included in the crossing over of genetic information that takes place between the pseudoautosomal regions of the X and Y chromosomes during meiosis in the father. When the X with the ''SRY'' gene combines with a normal X from the mother during fertilization, the result is an XX genetic male. Less common are ''SRY''-negative individuals, who appear to be XX genetic females, which is caused by a mutation in an autosomal or X chromosomal gene. Masculinization in those with the condition is variable, and those with the condition are sterile. This syndrome is diagnosed and occurs in appr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Male Infertility
Male infertility refers to a sexually mature male's inability to impregnate a fertile female. Male infertility can wholly or partially account for 40% of infertility among couples who are trying to have children. "A problem with the male is the sole cause, or a contributing cause, of infertility in about 40 percent of infertile couples. It affects approximately 7% of all men. Male infertility is commonly due to deficiencies in the semen, and semen quality is used as a surrogate measure of male fecundity. More recently, advance sperm analyses that examine intracellular sperm components are being developed. Age considerations Sperm motility increases from puberty through one's mid-thirties. Research shows that from the age of 36 onwards, sperm motility decreases from 40% Grade A & B to 31% in one's 50s. The effects of aging on semen quality is summarized below based on a study of 1,219 subjects: 90% of seminiferous tubules in men in their 20s and 30s contain spermatids, whereas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tigon
The tigon is a hybrid offspring of a male tiger (''Panthera tigris'') and a female lion, or lioness (''Panthera leo'').Techné v6n3 – Patenting and Transgenic Organisms: A Philosophical Exploration Scholar.lib.vt.edu. Retrieved on 17 September 2013. They exhibit visible characteristics from both parents: they can have both spots from the mother (lions carry genes for spots – lion cubs are spotted and some adults retain faint markings) and stripes from the father. Any mane that a male tigon may have will appear shorter and less noticeable than a lion's mane and is closer in type to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liger
The liger is a hybrid (biology), hybrid offspring of a male lion (''Panthera leo'') and a tigress, or female tiger (''Panthera tigris''). The liger has parents in the same genus but of different species. The liger is distinct from the opposite hybrid called the tigon (of a male tiger and a lioness), and is the largest of all known Extant taxon, extant Felidae, felids. They enjoy swimming, which is a characteristic of tigers, and are very sociable like lions. Notably, ligers typically grow larger than either parent species, unlike tigons.Ligers ''messybeast.com''. Retrieved 4 September 2012. History The history of lion–tiger hybrids dates to at least the early 19th century in India. In 1798, Étienne Geoffroy Saint-Hilaire (1772–1844) made a colour plate of the offspring of a lion and a tiger. The name "lig ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hinny
A hinny is a domestic equine hybrid, the offspring of a male horse (a stallion) and a female donkey (a jenny). It is the reciprocal cross to the more common mule, which is the product of a male donkey (a jack) and a female horse (a mare). The hinny is distinct from the mule both in physiology and temperament as a consequence of genomic imprinting and is also less common. Many supposed examples of the jumart, a supposed hybrid between a horse and a cow in European folklore, were found to be hinnies. Description The hinny is the offspring of a stallion and a jenny or female donkey, and is thus the reciprocal cross to the more common mule foaled by a jack (male donkey) out of a mare. Like the mule, the hinny displays hybrid vigour (heterosis). In general terms, in both these hybrids the foreparts and head of the animal are similar to those of the sire, while the hindparts and tail are more similar to those of the dam. A hinny is generally smaller than a mule, with sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sterile Insect Technique
The sterile insect technique (SIT) is a method of biological pest control, biological insect control, whereby overwhelming numbers of infertility, sterile insects are released into the wild. The released insects are preferably male, as this is more cost-effective and the females may in some situations cause damage by laying eggs in the crop, or, in the case of mosquitoes, taking blood from humans. The sterile males compete with fertile males to mate with the females. Females that mate with a sterile male produce no offspring, thus reducing the next generation's population. Sterile insects are not self-replicating and, therefore, cannot become established in the environment. Repeated release of sterile males over low population densities can further reduce and in cases of isolation eliminate pest populations, although cost-effective control with dense target populations is subjected to population suppression prior to the release of the sterile males. The technique has successfully ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Control
Biological control or biocontrol is a method of controlling pests, whether pest animals such as insects and mites, weeds, or pathogens affecting animals or plants by using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also involves an active human management role. It can be an important component of integrated pest management (IPM) programs. There are three basic strategies for biological control: classical (importation), where a natural enemy of a pest is introduced in the hope of achieving control; inductive (augmentation), in which a large population of natural enemies are administered for quick pest control; and inoculative (conservation), in which measures are taken to maintain natural enemies through regular reestablishment. Natural enemies of insects play an important part in limiting the densities of potential pests. Biological control agents such as these include predators, parasitoids, pathogens, and co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetically Modified Plants
Genetically modified plants have been engineered for scientific research, to create new colours in plants, deliver vaccines, and to create enhanced crops. Plant genomes can be engineered by physical methods or by use of ''Agrobacterium'' for the delivery of sequences hosted in T-DNA binary vectors. Many plant cells are pluripotent, meaning that a single cell from a mature plant can be harvested and then under the right conditions form a new plant. This ability is most often taken advantage by genetic engineers through selecting cells that can successfully be transformed into an adult plant which can then be grown into multiple new plants containing transgene in every cell through a process known as tissue culture. Research Much of the advances in the field genetic engineering has come from experimentation with tobacco. Major advances in tissue culture and plant cellular mechanisms for a wide range of plants has originated from systems developed in tobacco. It was the first plan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terminator Technology
Genetic use restriction technology (GURT), also known as terminator technology or suicide seeds, is designed to restrict access to "genetic materials and their associated phenotypic traits." The technology works by activating (or deactivating) specific genes using a controlled stimulus in order to cause second generation seeds to be either infertile or to not have one or more of the desired traits of the first generation plant. GURTs can be used by agricultural firms to enhance protection of their innovations in genetically modified organisms by making it impossible for farmers to reproduce the desired traits on their own. Another possible use is to prevent the escape of genes from genetically modified organisms into the surrounding environment. Patent applications related to a biological switch mechanism emerged in the early 1990's by companies such as DuPont and Zeneca (today Syngenta). Though the original GURT technology named "Technology Protection System" or "TPS" was devel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seedless Fruit
A seedless fruit is a fruit developed to possess no mature seeds. Since eating seedless fruits is generally easier and more convenient, they are considered commercially valuable. Most commercially produced seedless fruits have been developed from plants whose fruits normally contain numerous relatively large hard seeds distributed throughout the flesh of the fruit. Varieties Common varieties of seedless fruits include watermelons, tomatoes, and grapes (such as Termarina rossa). Additionally, there are numerous seedless citrus fruits, such as oranges, lemons and limes. A recent development over the last twenty years has been that of seedless sweet peppers (''Capsicum annuum''). The seedless plant combines male sterility in the pepper plant (commonly occurring) with the ability to set seedless fruits (a natural fruit-setting without fertilization). In male sterile plants, the parthenocarpy expresses itself only sporadically on the plant with deformed fruits. It has been repo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
