Search results
Results from the Tech24 Deals Content Network
Preimplantation genetic diagnosis. Preimplantation genetic diagnosis (PGD or PIGD) refers to genetic evaluation of embryos and oocytes prior to implantation. When used to screen for a specific genetic condition, the method also makes it possible to select embryos with intersex conditions for termination. Some national authorities, such as the ...
Chromosomes in humans can be divided into two types: autosomes (body chromosome (s)) and allosome ( sex chromosome (s)). Certain genetic traits are linked to a person's sex and are passed on through the sex chromosomes. The autosomes contain the rest of the genetic hereditary information. All act in the same way during cell division.
Genetic linkage. Genetic linkage is the tendency of DNA sequences that are close together on a chromosome to be inherited together during the meiosis phase of sexual reproduction. Two genetic markers that are physically near to each other are unlikely to be separated onto different chromatids during chromosomal crossover, and are therefore said ...
The XY sex-determination system is a sex-determination system used to classify 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 ...
The syndrome is diagnosed in an increasing number of children prenatally by amniocentesis and chorionic villus sampling [ 24] in order to obtain a chromosome karyotype, where the abnormality can be observed. It is estimated that only 15–20% of children with 47,XYY syndrome are ever diagnosed. Of these, approximately 30% are diagnosed prenatally.
Sex chromosomes (also referred to as allosomes, heterotypical chromosome, gonosomes, heterochromosomes, [1] [2] or idiochromosomes [1]) are chromosomes that carry the genes that determine the sex of an individual. The human sex chromosomes are a typical pair of mammal allosomes. They differ from autosomes in form, size, and behavior.
Chromosome 21 is one of the 23 pairs of chromosomes in humans. Chromosome 21 is both the smallest human autosome and chromosome, [4] with 46.7 million base pairs (the building material of DNA) representing about 1.5 percent of the total DNA in cells. Most people have two copies of chromosome 21, while those with three copies of chromosome 21 ...
Structure. In insects, polytene chromosomes are commonly found in the salivary glands; they are also referred to as "salivary gland chromosomes". The large size of the chromosome is due to the presence of many longitudinal strands called chromonemata; hence the name polytene (many stranded). They are about 0.5 mm in length and 20 μm in diameter.