Search results
Results from the WOW.Com Content Network
Lampbrush chromosome. Lampbrush chromosome are a special form of chromosome found in the growing oocytes (immature eggs) of most animals, except mammals. They were first described by Walther Flemming and Ruckert in 1882. [1] Lampbrush chromosomes of tailed and tailless amphibians, birds and insects are described best of all.
A well known balanced lethal system is the one fixed in the genus Triturus (containing the crested and the marbled newts). [4] Each of the homologous chromosomes of pair 1 (1A and 1B) has a different recessive deleterious allele on a non-recombining section of the chromosome. [2]
In humans, at least 20 of 23 chromosome ends have been shown to contain CpG islands, which are generally found at or near transcription start sites in the subtelomeric region. Within these CpG island are three repetitive DNA tracts occurring in sequence: a centromere-proximal tract of repeated 61-base-pair (bp) units; second, a more distal ...
These chromosomes consist of more than 1000 copies of the same chromatid that are aligned and produce alternating dark and light bands when stained. The dark bands are the chromomere. It is unknown when chromomeres first appear on the chromosome. Chromomeres can be observed best when chromosomes are highly condensed. [2]
A metaphase cell positive for the BCR/ABL rearrangement using FISH. 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. [1]
Population Genetics: Genetic distance can help in studying population genetics, understanding intra and inter-population genetic diversity. Taxonomy and Species Delimitation : Determining genetic distance through DNA barcoding is an effective tool for delimiting species especially identifying cryptic species . [ 15 ]
Endoreduplication is commonly observed in cells responsible for the nourishment and protection of oocytes and embryos. It has been suggested that increased gene copy number might allow for the mass production of proteins required to meet the metabolic demands of embryogenesis and early development. [ 1 ]
In 1980, W.M. Brown, looking at the relative variation between human and other species, recognized there was a recent constriction (180,000 years ago) in the human population. [9] A year later Brown and Wilson were looking at RFLP fragments and determined the human population expanded more recently than other ape populations. [ 10 ]