|
Spindle Transfer
Mitochondrial replacement therapy (MRT), sometimes called mitochondrial donation, is the replacement of mitochondria in one or more cells to prevent or ameliorate disease. MRT originated as a special form of in vitro fertilisation in which some or all of the future baby's mitochondrial DNA (mtDNA) comes from a third party. This technique is used in cases when mothers carry genes for mitochondrial diseases. The therapy is approved for use in the United Kingdom.Index page with links to summaries includin one page summary flyer A second ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrion
A mitochondrion () is an organelle found in the cell (biology), cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double lipid bilayer, membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy. They were discovered by Albert von Kölliker in 1857 in the voluntary muscles of insects. The term ''mitochondrion'', meaning a thread-like granule, was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase popularized by Philip Siekevitz in a 1957 ''Scientific American'' article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). The multicellular animal ''Henneguya zschokkei, Henneguya salminicola'' is known to have retained mitochondrion-related organelles despite a complete loss of their mitochondrial genome. A large number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryologist
Embryology (from Greek ἔμβρυον, ''embryon'', "the unborn, embryo"; and -λογία, ''-logia'') is the branch of animal biology that studies the prenatal development of gametes (sex cells), fertilization, and development of embryos and fetuses. Additionally, embryology encompasses the study of congenital disorders that occur before birth, known as teratology. Early embryology was proposed by Marcello Malpighi, and known as preformationism, the theory that organisms develop from pre-existing miniature versions of themselves. Aristotle proposed the theory that is now accepted, epigenesis. Epigenesis is the idea that organisms develop from seed or egg in a sequence of steps. Modern embryology developed from the work of Karl Ernst von Baer, though accurate observations had been made in Italy by anatomists such as Aldrovandi and Leonardo da Vinci in the Renaissance. Comparative embryology Preformationism and epigenesis As recently as the 18th century, the prevailing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haplotype
A haplotype (haploid genotype) is a group of alleles in an organism that are inherited together from a single parent. Many organisms contain genetic material (DNA) which is inherited from two parents. Normally these organisms have their DNA organized in two sets of pairwise similar chromosomes. The offspring gets one chromosome in each pair from each parent. A set of pairs of chromosomes is called diploid and a set of only one half of each pair is called haploid. The haploid genotype (haplotype) is a genotype that considers the singular chromosomes rather than the pairs of chromosomes. It can be all the chromosomes from one of the parents or a minor part of a chromosome, for example a sequence of 9000 base pairs or a small set of alleles. Specific contiguous parts of the chromosome are likely to be inherited together and not be split by chromosomal crossover, a phenomenon called genetic linkage. As a result, identifying these statistical associations and a few alleles of a specif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heteroplasmy
Heteroplasmy is the presence of more than one type of organellar genome (mitochondrial DNA or plastid DNA) within a cell or individual. It is an important factor in considering the severity of mitochondrial diseases. Because most eukaryotic cells contain many hundreds of mitochondria with hundreds of copies of mitochondrial DNA, it is common for mutations to affect only some mitochondria, leaving most unaffected. Although detrimental scenarios are well-studied, heteroplasmy can also be beneficial. For example, centenarians show a higher than average degree of heteroplasmy. At birth, all copies of mitochondrial DNA are thought to be identical in most humans. Microheteroplasmy is mutations of up to about 2−5% of mitochondrial genomes, and is present in most adults. This refers to hundreds of independent mutations in one organism, with each mutation found in about 1–2% of all mitochondrial genomes. Very low-level heteroplasmic variance is present in essentially all individua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Preimplantation Genetic Screening
Preimplantation genetic diagnosis (PGD or PIGD) is the genetic profiling of embryos prior to implantation (as a form of embryo profiling), and sometimes even of oocytes prior to fertilization. PGD is considered in a similar fashion to prenatal diagnosis. When used to screen for a specific genetic disease, its main advantage is that it avoids selective abortion, as the method makes it highly likely that the baby will be free of the disease under consideration. PGD thus is an adjunct to assisted reproductive technology, and requires in vitro fertilization (IVF) to obtain oocytes or embryos for evaluation. Embryos are generally obtained through blastomere or blastocyst biopsy. The latter technique has proved to be less deleterious for the embryo, therefore it is advisable to perform the biopsy around day 5 or 6 of development. The world's first PGD was performed by Handyside, Kontogianni and Winston at the Hammersmith Hospital in London. "Female embryos were selectively transferr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Assisted Reproductive Technology
Assisted reproductive technology (ART) includes medical procedures used primarily to address infertility. This subject involves procedures such as in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), and cryopreservation of gametes and embryos, and the use of fertility medication. When used to address infertility, ART may also be referred to as fertility treatment. ART mainly belongs to the field of reproductive endocrinology and infertility. Some forms of ART may be used with regard to fertile couples for genetic purpose (see preimplantation genetic diagnosis). ART may also be used in surrogacy arrangements, although not all surrogacy arrangements involve ART. The existence of sterility will not always require ART to be the first option to consider, as there are occasions when its cause is a mild disorder that can be solved with more conventional treatments or with behaviors based on promoting health and reproductive habits. Procedures General With ART, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autism Spectrum
Autism, also known as autism spectrum disorder (ASD), is a neurodevelopmental disorder characterized by differences or difficulties in social communication and interaction, a preference for predictability and routine, sensory processing differences, focused interests, and repetitive behaviors, which may include stimming. Formal diagnosis requires significant challenges in multiple domains of life, with characteristics that are atypical or more pronounced than expected for one's age and sociocultural context.(World Health Organization: International Classification of Diseases version 11 (ICD-11)): https://icd.who.int/browse/2024-01/mms/en#437815624 Motor coordination difficulties are common but not required for diagnosis. Autism is a spectrum disorder, resulting in wide variations in presentation and support needs, such as that between speaking and non-speaking populations. Increased estimates of autism prevalence since the 1990s are primarily attributed to broader cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pervasive Developmental Disorder
The diagnostic category pervasive developmental disorders (PDD), as opposed to specific developmental disorders (SDD), was a group of disorders characterized by delays in the development of multiple basic functions including socialization and communication. It was defined by the Diagnostic and Statistical Manual of Mental Disorders (DSM) (from 1980 to 2013), and the International Classification of Diseases (ICD) (until 2022). The pervasive developmental disorders included autism, Asperger syndrome, pervasive developmental disorder not otherwise specified (PDD-NOS), childhood disintegrative disorder (CDD), overactive disorder associated with intellectual disability and stereotyped movements, and Rett syndrome. As of the publication of the DSM-5 in 2013, the first four of these disorders are now known collectively as autism spectrum disorder; the last disorder is much rarer, and is sometimes placed on the autism spectrum and sometimes not. The onset of pervasive developmental ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turner's Syndrome
Turner syndrome (TS), commonly known as 45,X, or 45,X0,Also written as 45,XO. is a chromosomal disorder in which cells of females have only one X chromosome instead of two, or are partially missing an X chromosome (sex chromosome monosomy) leading to the complete or partial deletion of the pseudoautosomal regions (PAR1, PAR2) in the affected X chromosome. Typically, people have two sex chromosomes (XX for females or XY for males). The chromosomal abnormality is often present in just some cells, in which case it is known as Turner syndrome with mosaicism. 45,X0 with mosaicism can occur in males or females, but Turner syndrome without mosaicism only occurs in females. Signs and symptoms vary among those affected but often include additional skin folds on the neck, arched palate, low-set ears, low hairline at the nape of the neck, short stature, and lymphedema of the hands and feet. Those affected do not normally develop menstrual periods or mammary glands without hormone treat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epigenetic
In biology, epigenetics is the study of changes in gene expression that happen without changes to the DNA sequence. The Greek prefix ''epi-'' (ἐπι- "over, outside of, around") in ''epigenetics'' implies features that are "on top of" or "in addition to" the traditional (DNA sequence based) genetic mechanism of inheritance. Epigenetics usually involves a change that is not erased by cell division, and affects the regulation of gene expression. Such effects on cellular and physiological traits may result from environmental factors, or be part of normal development. The term also refers to the mechanism of changes: functionally relevant alterations to the genome that do not involve mutation of the nucleotide sequence. Examples of mechanisms that produce such changes are DNA methylation and histone modification, each of which alters how genes are expressed without altering the underlying DNA sequence. Further, non-coding RNA sequences have been shown to play a key role in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messenger RNA
In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of synthesizing a protein. mRNA is created during the process of transcription, where an enzyme (RNA polymerase) converts the gene into primary transcript mRNA (also known as pre-mRNA). This pre-mRNA usually still contains introns, regions that will not go on to code for the final amino acid sequence. These are removed in the process of RNA splicing, leaving only exons, regions that will encode the protein. This exon sequence constitutes mature mRNA. Mature mRNA is then read by the ribosome, and the ribosome creates the protein utilizing amino acids carried by transfer RNA (tRNA). This process is known as translation. All of these processes form part of the central dogma of molecular biology, which describes the flow of genetic information in a biological system. As in DNA, genetic inf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
