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Karl Sax
Karl Sax (November 2, 1892 – October 8, 1973) was an American botanist and geneticist, noted for his research in cytogenetics and the effect of radiation on chromosomes. Early life and education Sax was born in Spokane, Washington in 1892. His parents were pioneer farmers and active in civic affairs; his father was the mayor of Colville, Washington. Sax's early education was in the Colville schools, and in 1912 he continued his studies at Washington State College. He majored in agriculture, and his subsequent decision to undertake graduate work was influenced by the botanist and plant breeder Edward Gaines. In college, he met and married Hally Jolivette, his cytology teacher, and they later had three sons. Following his graduation, Hally accepted a position at Wellesley College in Wellesley, Massachusetts, and they moved to the East Coast in 1916. Sax enrolled in the doctoral program at the Bussey Institution Graduate School of Applied Biology at Harvard University in Cambridge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytogenetics
Cytogenetics is essentially a branch of genetics, but is also a part of cell biology/cytology (a subdivision of human anatomy), that is concerned with how the chromosomes relate to cell behaviour, particularly to their behaviour during mitosis and meiosis. Techniques used include karyotyping, analysis of G-banded chromosomes, other cytogenetic banding techniques, as well as molecular cytogenetics such as fluorescent ''in situ'' hybridization (FISH) and comparative genomic hybridization (CGH). History Beginnings Chromosomes were first observed in plant cells by Carl Nägeli in 1842. Their behavior in animal (salamander) cells was described by Walther Flemming, the discoverer of mitosis, in 1882. The name was coined by another German anatomist, von Waldeyer in 1888. The next stage took place after the development of genetics in the early 20th century, when it was appreciated that the set of chromosomes (the karyotype) was the carrier of the genes. Levitsky seems to have been t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crepis
''Crepis'', commonly known in some parts of the world as hawksbeard or hawk's-beard (but not to be confused with the related genus ''Hieracium'' with a similar common name), is a genus of annual and perennial flowering plants of the family Asteraceae superficially resembling the dandelion, the most conspicuous difference being that ''Crepis'' usually has branching scapes with multiple heads (though solitary heads can occur). The genus name ''Crepis'' derives from the Greek ''krepis'', meaning "slipper" or "sandal", possibly in reference to the shape of the fruit.''Crepis''. Flora of North America. The genus is distributed throughout the Northern Hemisphere and |
Prunus Subhirtella
''Prunus'' is a genus of trees and shrubs, which includes (among many others) the fruits plums, cherries, peaches, nectarines, apricots, and almonds. Native to the North American temperate regions, the neotropics of South America, and the paleotropics of Asia and Africa, 430 different species are classified under ''Prunus''. Many members of the genus are widely cultivated for their fruit and for decorative purposes. ''Prunus'' fruit are drupes, or stone fruits. The fleshy mesocarp surrounding the endocarp is edible while the endocarp itself forms a hard, inedible shell called the pyrena ("stone" or "pit"). This shell encloses the seed (or "kernel") which is edible in many species (such as almonds) but poisonous in others (such as apricots). Besides being eaten off the hand, most ''Prunus'' fruit are also commonly used in processing, such as jam production, canning, drying, and seeds for roasting. Botany Members of the genus can be deciduous or evergreen. A few species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cherries
A cherry is the fruit of many plants of the genus ''Prunus'', and is a fleshy drupe (stone fruit). Commercial cherries are obtained from cultivars of several species, such as the sweet ''Prunus avium'' and the sour ''Prunus cerasus''. The name 'cherry' also refers to the cherry tree and its wood, and is sometimes applied to almonds and visually similar flowering trees in the genus ''Prunus'', as in " ornamental cherry" or "cherry blossom". Wild cherry may refer to any of the cherry species growing outside cultivation, although ''Prunus avium'' is often referred to specifically by the name "wild cherry" in the British Isles. Botany True cherries ''Prunus'' subg. ''Cerasus'' contains species that are typically called cherries. They are known as true cherries and distinguished by having a single winter bud per axil, by having the flowers in small corymbs or umbels of several together (occasionally solitary, e.g. ''P. serrula''; some species with short racemes, e.g. '' P. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forsythia
''Forsythia'' , is a genus of flowering plants in the olive family Oleaceae. There are about 11 species, mostly native to eastern Asia, but one native to southeastern Europe. ''Forsythia'' – also one of the plant's common names – is named after William Forsyth.Flora of China''Forsythia''/ref>Flora Europaea''Forsythia''/ref>St Andrews Botanic Garden Description ''Forsythia'' are deciduous shrubs typically growing to a height of and, rarely, up to with rough grey-brown bark. The leaves are borne oppositely and are usually simple, though sometimes trifoliate with a basal pair of small leaflets; they range between in length and, rarely, up to , with a margin that is serrated or entire (smooth). Twigs may be hollow or chambered, depending on the species. The flowers are produced in the early spring before the leaves, bright yellow with a deeply four-lobed flower, the petals joined only at the base. These become pendent in rainy weather thus shielding the reproductive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnolia
''Magnolia'' is a large genus of about 210 to 340The number of species in the genus ''Magnolia'' depends on the taxonomic view that one takes up. Recent molecular and morphological research shows that former genera ''Talauma'', ''Dugandiodendron'', ''Manglietia'', ''Michelia'', ''Elmerrillia'', ''Kmeria'', ''Parakmeria'', ''Pachylarnax'' (and a small number of monospecific genera) all belong within the same genus, ''Magnolia'' s.l. (s.l. = ''sensu lato'': 'in a broad sense', as opposed to s.s. = ''sensu stricto'': 'in a narrow sense'). The genus ''Magnolia'' s.s. contains about 120 species. See the section Nomenclature and classification in this article. flowering plant species in the subfamily Magnolioideae of the family Magnoliaceae. It is named after French botanist Pierre Magnol. ''Magnolia'' is an ancient genus. Appearing before bees evolved, the flowers are theorized to have evolved to encourage pollination by beetles. To avoid damage from pollinating beetles, the carpe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apples
An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, where its wild ancestor, ''Malus sieversii'', is still found today. Apples have been grown for thousands of years in Asia and Europe and were brought to North America by European colonization of the Americas, European colonists. Apples have Religion, religious and mythology, mythological significance in many cultures, including Norse mythology, Norse, Greek mythology, Greek, and Christianity in Europe, European Christian tradition. Apples grown from seed tend to be very different from those of their parents, and the resultant fruit frequently lacks desired characteristics. Generally, apple cultivars are propagated by clonal grafting onto rootstocks. Apple trees grown without rootstocks tend to be larger and much slower to fruit after plantin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malus
''Malus'' ( or ) is a genus of about 30–55 species of small deciduous trees or shrubs in the family Rosaceae, including the domesticated orchard apple, crab apples, wild apples, and rainberries. The genus is native to the temperate zone of the Northern Hemisphere. Description Apple trees are typically talI at maturity, with a dense, twiggy crown. The leaves are long, alternate, simple, with a serrated margin. The flowers are borne in corymbs, and have five petals, which may be white, pink, or red, and are perfect, with usually red stamens that produce copious pollen, and a half-inferior ovary; flowering occurs in the spring after 50–80 growing degree days (varying greatly according to subspecies and cultivar). Many apples require cross-pollination between individuals by insects (typically bees, which freely visit the flowers for both nectar and pollen); these are called self-sterile, so self-pollination is impossible, making pollinating insects essential. A number o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome Abnormality
A chromosomal abnormality, chromosomal anomaly, chromosomal aberration, chromosomal mutation, or chromosomal disorder, is a missing, extra, or irregular portion of chromosomal DNA. These can occur in the form of numerical abnormalities, where there is an atypical number of chromosomes, or as structural abnormalities, where one or more individual chromosomes are altered. Chromosome mutation was formerly used in a strict sense to mean a change in a chromosomal segment, involving more than one gene. Chromosome anomalies usually occur when there is an error in cell division following meiosis or mitosis. Chromosome abnormalities may be detected or confirmed by comparing an individual's karyotype, or full set of chromosomes, to a typical karyotype for the species via genetic testing. Numerical abnormality An abnormal number of chromosomes is called aneuploidy, and occurs when an individual is either missing a chromosome from a pair (resulting in monosomy) or has more than two chromosome ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosomal Translocations
In genetics, chromosome translocation is a phenomenon that results in unusual rearrangement of chromosomes. This includes balanced and unbalanced translocation, with two main types: reciprocal-, and Robertsonian translocation. Reciprocal translocation is a chromosome abnormality caused by exchange of parts between non-homologous chromosomes. Two detached fragments of two different chromosomes are switched. Robertsonian translocation occurs when two non-homologous chromosomes get attached, meaning that given two healthy pairs of chromosomes, one of each pair "sticks" and blends together homogeneously. A gene fusion may be created when the translocation joins two otherwise-separated genes. It is detected on cytogenetics or a karyotype of affected cells. Translocations can be balanced (in an even exchange of material with no genetic information extra or missing, and ideally full functionality) or unbalanced (where the exchange of chromosome material is unequal resulting in extra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetics
Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar working in the 19th century in Brno, was the first to study genetics scientifically. Mendel studied "trait inheritance", patterns in the way traits are handed down from parents to offspring over time. He observed that organisms (pea plants) inherit traits by way of discrete "units of inheritance". This term, still used today, is a somewhat ambiguous definition of what is referred to as a gene. Trait inheritance and molecular inheritance mechanisms of genes are still primary principles of genetics in the 21st century, but modern genetics has expanded to study the function and behavior of genes. Gene structure and function, variation, and distribution are studied within the context of the cell, the organism (e.g. dominance), and within the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forsythia Close-up 2 Cropped
''Forsythia'' , is a genus of flowering plants in the olive family Oleaceae. There are about 11 species, mostly native to eastern Asia, but one native to southeastern Europe. ''Forsythia'' – also one of the plant's common names – is named after William Forsyth.Flora of China''Forsythia''/ref>Flora Europaea''Forsythia''/ref>St Andrews Botanic Garden Description ''Forsythia'' are deciduous shrubs typically growing to a height of and, rarely, up to with rough grey-brown bark. The leaves are borne oppositely and are usually simple, though sometimes trifoliate with a basal pair of small leaflets; they range between in length and, rarely, up to , with a margin that is serrated or entire (smooth). Twigs may be hollow or chambered, depending on the species. The flowers are produced in the early spring before the leaves, bright yellow with a deeply four-lobed flower, the petals joined only at the base. These become pendent in rainy weather thus shielding the reproductive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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