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Heterozygotes
Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. Diploid organisms have the same loci on each of their two sets of homologous chromosomes except that the sequences at these loci may differ between the two chromosomes in a matching pair and that a few chromosomes may be mismatched as part of a chromosomal sex-determination system. If both alleles of a diploid organism are the same, the organism is homozygous at that locus. If they are different, the organism is heterozygous at that locus. If one allele is missing, it is hemizygous, and, if both alleles are missing, it is nullizygous. The DNA sequence of a gene often varies from one individual to another. These gene variants are called alleles. While some gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genotype
The genotype of an organism is its complete set of genetic material. Genotype can also be used to refer to the alleles or variants an individual carries in a particular gene or genetic location. The number of alleles an individual can have in a specific gene depends on the number of copies of each chromosome found in that species, also referred to as ploidy. In diploid species like humans, two full sets of chromosomes are present, meaning each individual has two alleles for any given gene. If both alleles are the same, the genotype is referred to as Zygosity, homozygous. If the alleles are different, the genotype is referred to as heterozygous. Genotype contributes to phenotype, the observable traits and characteristics in an individual or organism. The degree to which genotype affects phenotype depends on the trait. For example, the petal color in a pea plant is exclusively determined by genotype. The petals can be purple or white depending on the alleles present in the pea plan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterozygous
Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. Diploid organisms have the same locus (genetics), loci on each of their two sets of homologous chromosomes except that the sequences at these loci may differ between the two chromosomes in a matching pair and that a few chromosomes may be mismatched as part of a chromosomal Sex-determination system#Chromosomal determination, sex-determination system. If both alleles of a diploid organism are the same, the organism is #Homozygous, homozygous at that locus. If they are different, the organism is #Heterozygous, heterozygous at that locus. If one allele is missing, it is #Hemizygous, hemizygous, and, if both alleles are missing, it is #Nullizygous, nullizygous. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pronucleus
A pronucleus (: pronuclei) denotes the nucleus found in either a sperm or egg cell during the process of fertilization. The sperm cell undergoes a transformation into a pronucleus after entering the egg cell but prior to the fusion of the genetic material of both the sperm and egg. In contrast, the egg cell possesses a pronucleus once it becomes haploid, not upon the arrival of the sperm cell. Haploid cells, such as sperm and egg cells in humans, carry half the number of chromosomes present in somatic cells, with 23 chromosomes compared to the 46 found in somatic cells. It is noteworthy that the male and female pronuclei do not physically merge, although their genetic material does. Instead, their membranes dissolve, eliminating any barriers between the male and female chromosomes, facilitating the combination of their chromosomes into a single diploid nucleus in the resulting embryo, which contains a complete set of 46 chromosomes. The presence of two pronuclei serves as the in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microinjection
Microinjection is the use of a glass micropipette to inject a liquid substance at a microscopic or borderline macroscopic level. The target is often a living cell but may also include intercellular space. Microinjection is a simple mechanical process usually involving an inverted microscope with a Optical power, magnification power of around 200x (though sometimes it is performed using a dissecting stereo microscope at 40–50x or a traditional Optical microscope#Compound microscope, compound upright microscope at similar power to an inverted model). For processes such as cellular or pronucleus, pronuclear injection the target cell is positioned under the microscope and two micromanipulation, micromanipulators—one holding the pipette and one holding a microcapillary needle usually between 0.5 and 5 μm in diameter (larger if injecting stem cells into an embryo)—are used to penetrate the cell membrane and/or the nuclear envelope. In this way the process can be used to int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Y Chromosome
The Y chromosome is one of two sex chromosomes in therian mammals and other organisms. Along with the X chromosome, it is part of the XY sex-determination system, in which the Y is the sex-determining chromosome because the presence of the Y chromosome causes offspring produced in sexual reproduction to be of male sex. In mammals, the Y chromosome contains the SRY gene, which triggers development of male gonads. The Y chromosome is passed only from male parents to male offspring. Overview Discovery The Y chromosome was identified as a sex-determining chromosome by Nettie Stevens at Bryn Mawr College in 1905 during a study of the mealworm ''Tenebrio molitor''. Edmund Beecher Wilson independently discovered the same mechanisms the same year, working with Hemiptera. Stevens proposed that chromosomes always existed in pairs and that the smaller chromosome (now labelled "Y") was the pair of the X chromosome discovered in 1890 by Hermann Henking. She realized that th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X Chromosome
The X chromosome is one of the two sex chromosomes in many organisms, including mammals, and is found in both males and females. It is a part of the XY sex-determination system and XO sex-determination system. The X chromosome was named for its unique properties by early researchers, which resulted in the naming of its counterpart Y chromosome, for the next letter in the alphabet, following its subsequent discovery. Discovery It was first noted that the X chromosome was special in 1890 by Hermann Henking in Leipzig. Henking was studying the testicles of '' Pyrrhocoris'' and noticed that one chromosome did not take part in meiosis. Chromosomes are so named because of their ability to take up staining (''chroma'' in Greek means ''color''). Although the X chromosome could be stained just as well as the others, Henking was unsure whether it was a different class of the object and consequently named it ''X element'', which later became X chromosome after it was established that it w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haploinsufficiency
Haploinsufficiency in genetics describes a model of dominant gene action in diploid organisms, in which a single copy of the wild-type allele at a locus in heterozygous combination with a variant allele is insufficient to produce the wild-type phenotype. Haploinsufficiency may arise from a ''de novo'' or inherited loss-of-function mutation in the variant allele, such that it yields little or no gene product (often a protein). Although the other, standard allele still produces the standard amount of product, the total product is insufficient to produce the standard phenotype. This heterozygous genotype may result in a non- or sub-standard, deleterious, and (or) disease phenotype. Haploinsufficiency is the standard explanation for dominant deleterious alleles. In the alternative case of haplosufficiency, the loss-of-function allele behaves as above, but the single standard allele in the heterozygous genotype produces sufficient gene product to produce the same, standard phenotyp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterogametic Sex
The XY sex-determination system is a sex-determination system present in many mammals (including humans), some insects ('' Drosophila''), some snakes, some fish ( guppies), and some plants (''Ginkgo'' tree). In this system, the sex of an individual usually is determined by a pair of sex chromosomes. Typically, females have two of the same kind of sex chromosome (XX), and are called the homogametic sex. Males typically have two different kinds of sex chromosomes (XY), and are called the heterogametic sex. In humans, the presence of the Y chromosome is responsible for triggering male development; in the absence of the Y chromosome, the fetus will undergo female development. In most species with XY sex determination, an organism must have at least one X chromosome in order to survive. The XY system contrasts in several ways with the ZW sex-determination system found in birds, some insects, many reptiles, and various other animals, in which the heterogametic sex is female. A te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noord Hollands Blauw, Kuikens, 6 Weken
Noord () is a town and region in Aruba (part of the Kingdom of the Netherlands). This town is known for its low rise and high rise hotels, restaurants, beaches, malls, the California Lighthouse, and other places of attraction. Places of interest in Noord include Alto Vista Chapel, Bubali Bird Sanctuary, California Lighthouse, Palm Beach and Arashi Beach. Tanki Flip The town of Tanki Flip is home to an Amerindian settlement whose remains date from 1000 to 1500. The village contained several '' malocas'' (long houses) with several smaller round houses and a central hut surrounded by an open plaza. The village was fenced off and inhabited by Caquetio people. Cas Tan Tin Cas Tan Tin is a ''cunucu'' (rural) house in Noord. It was built by Mario and Johanna Tromp in the early 20th century. They raised nine children and grew fruits and vegetables at Cas Tan Tin. Nowadays it is located in the suburban sprawl. In 2019, it was bought by the , because it is a traditional house in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterozygote Advantage
A heterozygote advantage describes the case in which the heterozygous genotype has a higher relative fitness (biology), fitness than either the homozygous Dominance (genetics), dominant or homozygous recessive gene, recessive genotype. Loci exhibiting heterozygote advantage are a small minority of loci. The specific case of heterozygote advantage due to a single locus (genetics), locus is known as overdominance. Overdominance is a rare condition in genetics where the phenotype of the heterozygote lies outside of the phenotypical range of both homozygote parents, and heterozygous individuals have a higher fitness (biology), fitness than homozygous individuals. Polymorphism (biology), Polymorphism can be maintained by Natural selection, selection favoring the heterozygote, and this mechanism is used to explain the occurrence of some kinds of genetic variation, genetic variability. A common example is the case where the heterozygote conveys both advantages and disadvantages, while bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dominant Allele
In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and the second is called recessive. This state of having two different variants of the same gene on each chromosome is originally caused by a mutation in one of the genes, either new (''de novo'') or inherited. The terms autosomal dominant or autosomal recessive are used to describe gene variants on non-sex chromosomes ( autosomes) and their associated traits, while those on sex chromosomes (allosomes) are termed X-linked dominant, X-linked recessive or Y-linked; these have an inheritance and presentation pattern that depends on the sex of both the parent and the child (see Sex linkage). Since there is only one Y chromosome, Y-linked traits cannot be dominant or recessive. Additionally, there are other forms of dominance, such as incompl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ploidy
Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, respectively, in each homologous chromosome pair—the form in which chromosomes naturally exist. Somatic cells, tissues, and individual organisms can be described according to the number of sets of chromosomes present (the "ploidy level"): monoploid (1 set), diploid (2 sets), triploid (3 sets), tetraploid (4 sets), pentaploid (5 sets), hexaploid (6 sets), heptaploid or septaploid (7 sets), etc. The generic term polyploid is often used to describe cells with three or more sets of chromosomes. Virtually all sexually reproducing organisms are made up of somatic cells that are diploid or greater, but ploidy level may vary widely between different organisms, between different tissues within the same organism, and at different stages in an o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
