A karyotype is the complete set of all chromosomes of a cell of any living organism. The chromosomes are arranged and displayed (often on a photo) in a standard format: in pairs, ordered by size. Karyotypes are examined in searches for chromosomal aberrations, and may be used to determine other macroscopically visible aspects of an individual's genotype, such as sex (XX vs. XY pair). The s ...

Including:

Karyotype - Classic karyotype Karyotype - Spectral karyotype SKY technique

Read more here: » Karyotype: Encyclopedia - Karyotype

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Chromosome, Chromosome - Chromosomes in plants yeast and animals, Chromosome - Chromosomes in bacteria, Chromosome - Chromatin, Chromosome - Number of chromosomes in different species, Chromosome - Karyotype, Chromosome - Human, Chromosome - Chromosomal aberrations

Read more here: » Chromosome: Encyclopedia II - Chromosome - Chromosomes in bacteria

Definition and meaning of karyotype:

karyotype - the entire chromosome complement of an individual cell, as seen during the mitotic phase

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The DNA which carries genetic information in biological cells is normally packaged in the form of one or more large macromolecules called chromosomes. A chromosome (in Greek chroma = color and soma = body) is, minimally, a very long, continuous piece of DNA, which contains many genes, regulatory elements and other intervening nucleotide sequences. In the chromosomes of eukaryotes, the uncondensed DNA exists in a quasi-ordered structure inside the nucleus, where it wraps around histones (structural proteins, Fig. 1 ...

Including:

Chromosome - Chromosomes in plants yeast and animals Chromosome - Chromosomes in bacteria Chromosome - Chromatin Chromosome - Number of chromosomes in different species Chromosome - Karyotype Chromosome - Human Chromosome - Chromosomal aberrations

Read more here: » Chromosome: Encyclopedia - Chromosome

Two types of chromatin can be distinguished: Euchromatin, which consists of DNA that is active, e.g., expressed as protein. Heterochromatin, which consists of mostly inactive DNA. It seems to serve structural purposes during the chromosomal stages. Heterochromatin can be further distinguished into two types: Constitutive heterochromatin, which is never expressed. It is located around the centromere and usually contains repetitive sequences. Facultative heterochromatin, which is ...

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Chromosome, Chromosome - Chromosomes in plants yeast and animals, Chromosome - Chromosomes in bacteria, Chromosome - Chromatin, Chromosome - Number of chromosomes in different species, Chromosome - Karyotype, Chromosome - Human, Chromosome - Chromosomal aberrations

Read more here: » Chromosome: Encyclopedia II - Chromosome - Chromatin

Normal members of a particular species all have the same number of chromosomes (see the table). Asexually reproducing species have one set of chromosomes, which is the same in all body cells. Gametes, reproductive cells, are haploid [n] and have one set of chromosomes. Sexually reproducing species have somatic cells, body cells, which are diploid [2n] having two sets of chromosomes, one from the mother and one from the father. Gametes are produced by meiosis of a diploid germ line cell. During meiosis, the matching chrom ...

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Chromosome, Chromosome - Chromosomes in plants yeast and animals, Chromosome - Chromosomes in bacteria, Chromosome - Chromatin, Chromosome - Number of chromosomes in different species, Chromosome - Karyotype, Chromosome - Human, Chromosome - Chromosomal aberrations

Read more here: » Chromosome: Encyclopedia II - Chromosome - Number of chromosomes in different species

Some chromosome abnormalities do not cause disease in carriers, such as translocations, or chromosomal inversions, although they may lead to a higher chance of having a child with a chromosome disorder. Abnormal numbers of chromosomes or chromosome sets, aneuploidy, may be lethal or give rise to genetic disorders. Genetic counseling is offered for families that may carry a chromosome rearrangement. The gain or loss of chromosome material can lead to a variety of genetic disorders. Examples include: Cri du chat, which is c ...

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Chromosome, Chromosome - Chromosomes in plants yeast and animals, Chromosome - Chromosomes in bacteria, Chromosome - Chromatin, Chromosome - Number of chromosomes in different species, Chromosome - Karyotype, Chromosome - Human, Chromosome - Chromosomal aberrations

Read more here: » Chromosome: Encyclopedia II - Chromosome - Chromosomal aberrations

In genetics, a chromosome translocation is the interchange of parts between nonhomologous chromosomes. It is detected on cytogenetics or a karyotype of affected cells. There are two main types, reciprocal and Robertsonian. Also, translocations can be balanced (in an even exchange of material with no genetic information extra or missing) or unbalanced (where the exchange of chromosome material is unequal resulting in extra or missing genes). Chromosomal translocation - Reciprocal Translocations. < ...

Including:

Chromosomal translocation - Reciprocal Translocations Chromosomal translocation - Robertsonian translocations Chromosomal translocation - Notation

Read more here: » Chromosomal translocation: Encyclopedia - Chromosomal translocation

XYY syndrome is a aneuploidy of the sex chromosomes in which a human male receives an extra Y chromosome in each cell, hence having a karyotype of 47,XYY. XYY syndrome is also called Jacob's Syndrome, XYY-trisomy, 47,XYY aneuploidy, or Supermale syndrome. XYY syndrome - First case. The first published report of a man with a 47,XYY chromosome constitution was by Dr. Avery A. Sandberg, et al. of Buffalo, New York in 1961. It was an incidental finding in a normal 44-year-old, ...

Including:

XYY syndrome - First case XYY syndrome - Effects
XYY syndrome - Physical traits XYY syndrome - Behavioral characteristics
XYY syndrome - Cause and prevalence

Read more here: » XYY syndrome: Encyclopedia - XYY syndrome

Normal members of a particular species all have the same number of chromosomes (see the table). Asexually reproducing species have one set of chromosomes, which is the same in all body cells. Gametes, reproductive cells, are haploid [n] and have one set of chromosomes. Sexually reproducing species have somatic cells, body cells, which are diploid [2n] having two sets of chromosomes, one from the mother and one from the father. Gametes are produced by meiosis of a diploid germ line cell. During meiosis, the matching chromosomes ...

See also:

Chromosome, Chromosome - History, Chromosome - Chromosomes in plants yeast and animals, Chromosome - Chromosomes in bacteria, Chromosome - Chromatin, Chromosome - Number of chromosomes in different species, Chromosome - Karyotype, Chromosome - Human, Chromosome - Chromosomal aberrations

Read more here: » Chromosome: Encyclopedia II - Chromosome - Number of chromosomes in different species

Some chromosome abnormalities do not cause disease in carriers, such as translocations, or chromosomal inversions, although they may lead to a higher chance of having a child with a chromosome disorder. Abnormal numbers of chromosomes or chromosome sets, aneuploidy, may be lethal or give rise to genetic disorders. Genetic counseling is offered for families that may carry a chromosome rearrangement. The gain or loss of chromosome material can lead to a variety of genetic disorders. Examples include: Cri du chat, which is c ...

See also:

Chromosome, Chromosome - History, Chromosome - Chromosomes in plants yeast and animals, Chromosome - Chromosomes in bacteria, Chromosome - Chromatin, Chromosome - Number of chromosomes in different species, Chromosome - Karyotype, Chromosome - Human, Chromosome - Chromosomal aberrations

Read more here: » Chromosome: Encyclopedia II - Chromosome - Chromosomal aberrations

This type of rearrangement involves two acrocentric chromosomes that fuse near the centromere region with loss of the short arms. The resulting karyotype has only 45 chromosomes since two chromosomes have fused together. Robertsonian translocations have been seen involving all combinations of acrocentric chromosomes. The most common translocation involves chromosomes 13 and 14 is seen in about 1 in 1300 persons, making it the most common chromosome rearrangement in humans. Like other translocations, carriers of Robertsonian transloca ...

See also:

Chromosomal translocation, Chromosomal translocation - Reciprocal Translocations, Chromosomal translocation - Robertsonian translocations, Chromosomal translocation - Notation

Read more here: » Chromosomal translocation: Encyclopedia II - Chromosomal translocation - Robertsonian translocations

This type of rearrangement involves two acrocentric chromosomes that fuse near the centromere region with loss of the short arms. The resulting karyotype has only 45 chromosomes since two chromosomes have fused together. Robertsonian translocations have been seen involving all combinations of acrocentric chromosomes. The most common translocation involves chromosomes 13 and 14 is seen in about 1 in 1300 persons, making it the most common chromosome rearrangement in humans. Like other translocations, carriers of Robertsonian translocations ar ...

See also:

Chromosomal translocation, Chromosomal translocation - Reciprocal translocations, Chromosomal translocation - Robertsonian translocations, Chromosomal translocation - Notation

Read more here: » Chromosomal translocation: Encyclopedia II - Chromosomal translocation - Robertsonian translocations

Two types of chromatin can be distinguished: Euchromatin, which consists of DNA that is active, e.g., expressed as protein. Heterochromatin, which consists of mostly inactive DNA. It seems to serve structural purposes during the chromosomal stages. Heterochromatin can be further distinguished into two types: Constitutive heterochromatin, which is never expressed. It is located around the centromere and usually contains repetitive sequences. Facultative heterochromatin, which is ...

See also:

Chromosome, Chromosome - History, Chromosome - Chromosomes in plants yeast and animals, Chromosome - Chromosomes in bacteria, Chromosome - Chromatin, Chromosome - Number of chromosomes in different species, Chromosome - Karyotype, Chromosome - Human, Chromosome - Chromosomal aberrations

Read more here: » Chromosome: Encyclopedia II - Chromosome - Chromatin

Bacterial chromosomes are often circular but sometimes linear. Some bacteria have one chromosome, while others have a few. Bacterial DNA also exists as plasmids. The distinction between plasmids and chromosomes is poorly defined, though size and necessity are generally taken into account. Bacterial chromosomes initiate replication and one origin of replication. When linear, bacterial chromosomes tend to be tethered to the plasma membrane of the bacteria. In molecular biology application, this allows for its isolation from plasmid DNA by centrifugation of lysed bacte ...

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Chromosome, Chromosome - History, Chromosome - Chromosomes in plants yeast and animals, Chromosome - Chromosomes in bacteria, Chromosome - Chromatin, Chromosome - Number of chromosomes in different species, Chromosome - Karyotype, Chromosome - Human, Chromosome - Chromosomal aberrations

Read more here: » Chromosome: Encyclopedia II - Chromosome - Chromosomes in bacteria

Reduced ability of a XY karyotype fetus to respond to androgens can result in one of several problems, including infertility and several forms of intersex conditions. See androgen insensitivity syndrome (AIS). ...

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Androgen, Androgen - Types of androgens, Androgen - Androgen functions, Androgen - Development of the male, Androgen - Spermatogenesis, Androgen - Inhibition of fat deposition, Androgen - Muscle mass, Androgen - Brain, Androgen - Insensitivity to androgen in humans

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John Langdon Down first characterized Down syndrome in 1862. Because of his perception that Down syndrome children share physical similarities with Mongolians, he used the terms mongolism or mongolian idiocy. In 1959, Professor Jérome Lejeune discovered that Down syndrome is a chromosomal irregularity [1]. The chromosomal irregularity was identified as trisomy 21. The human karyotype is numbered from largest to smallest (excluding the X and Y). Lejeune ascribed the trisomy to chromosome 21, the second smallest. H ...

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Down syndrome, Down syndrome - Overview, Down syndrome - History, Down syndrome - Medical research, Down syndrome - Down Syndrome's sociology, Down syndrome - Notable individuals, Down syndrome - Down syndrome in fiction, Down syndrome - Sources

Read more here: » Down syndrome: Encyclopedia II - Down syndrome - History

The XXY chromosome arrangement is one of the most common genetic variations from the XY karyotype, occurring in about 1 in 1,000 male births. Because of the extra chromosome, individuals with the condition are usually referred to as "XXY Males", or "47,XXY Males" rather than as "suffering from Klinefelter's syndrome." In mammals with more than one X chromosome, the genes on all but one X chromosome are barred from being expressed. This happens in XXY males as well as XX females. A few genes, however, have corresponding genes on the Y chromosome and are not barred. These triploid genes in XXY males may be responsible for ...

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Klinefelter's syndrome, Klinefelter's syndrome - Cause, Klinefelter's syndrome - Signs and symptoms, Klinefelter's syndrome - Treatment, Klinefelter's syndrome - Reference

Read more here: » Klinefelter's syndrome: Encyclopedia II - Klinefelter's syndrome - Cause

The condition is irreversible, but its symptoms can be altered in a number of ways, including testosterone treatment and other therapies. While the gender identity of people with XXY karyotype is generally stable, the number of people with gender identity disorder among the whole seems to be higher than could statistically be expected if those cases were indeed, as the current medical opinion assesses, mere coincidences of people having both gender identity disorder and Klinefelter's independently from each other. The observation on g ...

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Klinefelter's syndrome, Klinefelter's syndrome - Cause, Klinefelter's syndrome - Signs and symptoms, Klinefelter's syndrome - Treatment, Klinefelter's syndrome - Reference

Read more here: » Klinefelter's syndrome: Encyclopedia II - Klinefelter's syndrome - Treatment

Turner syndrome may be diagnosed by an amniocentesis during pregnancy. Sometimes, fetuses with Turner syndrome are identified by abnormal ultrasound findings (i.e. heart defect, kidney abnormality, cystic hygroma, ascities). Although the recurrence risk is not increased, genetic counseling is often recommended for families who have had a pregnancy or child with Turner syndrome. A blood test, called a karyotype, analyzes the chromosomal composition of the individual. This is the most commonly ...

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Turner syndrome, Turner syndrome - Symptoms, Turner syndrome - Causes, Turner syndrome - Incidence, Turner syndrome - History, Turner syndrome - Diagnosis, Turner syndrome - Medical consequences of Turner syndrome, Turner syndrome - Cardiovascular, Turner syndrome - Skeletal, Turner syndrome - Kidney, Turner syndrome - Thyroid, Turner syndrome - Diabetes, Turner syndrome - Cognitive, Turner syndrome - Reproductive, Turner syndrome - Treatment

Read more here: » Turner syndrome: Encyclopedia II - Turner syndrome - Diagnosis