A dense object lying along the inside of the nuclear envelope in cells of female mammals, representing a highly condensed, inactivated X chromosome.
chromosome theory of inheritance
A basic principle in biology stating that genes are located at specific positions (loci) on chromosomes and that the behavior of chromosomes during meiosis accounts for inheritance patterns
(1) A deficiency in a chromosome resulting from the loss of a fragment through breakage. (2) A mutational loss of one or more nucleotide pairs from a gene.
An aberration in chromosome structure due to fusion with a fragment from a homologous chromosome, such that a portion of a chromosome is duplicated
An ordered list of genetic loci (genes or other genetic markers) along a chromosome.
General term for the production of offspring with combinations of traits that differ from those found in either parent.
An aberration in chromosome structure resulting from reattachment of a chromosomal fragment in a reverse orientation to the chromosome from which it originated
A genetic map based on the frequencies of recombination between markers during crossing over of homologous chromosomes.
Genes located close enough together on a chromosome that they tend to be inherited together.
A unit of measurement of the distance between genes. One map unit is equivalent to a 1% recombination frequency.
Referring to a diploid cell that has only one copy of a particular chromosome instead of the normal two
An error in meiosis or mitosis in which members of a pair of homologous chromosomes or a pair of sister chromatids fail to separate properly from each other
recombinant type (recombinant)
An offspring whose phenotype differs from that of the true-breeding P generation parents; also refers to the phenotype itself.
A gene located on either sex chromosome. Most sex-linked genes are on the X chromosome and show distinctive patterns of inheritance; there are very few genes on the Y chromosome.
Referring to a diploid cell that has three copies of a particular chromosome instead of the normal two
The phenotype most commonly observed in natural populations; also refers to the individual with that phenotype.
A gene located on the X chromosome; such genes show a distinctive pattern of inheritance.
An aberration in chromosome structure resulting from attachment of a chromosomal fragment to a nonhomologous chromosome
A chromosomal alteration in which the organism possesses more than two complete chromosome sets. It is a result of an accident in cell division.
Duchenne muscular dystrophy
A human genetic disease caused by a sex-linked recessive allele; characterized b progressive weakening and loss of muscle tissue
A human genetic disease caused by a sex-liked recessive allele resulting in the absence of one or more blood-clotting proteins; characterized by excessive bleeding following an injury.
A human genetic disorder usually caused by the presence of an extra chromosome 21, characterized by developmental delays and heart and other defects that are generally treatable or non-life-threatening
A chromosomal aberration in which one or more chromosomes are present in extra copies or are deficient in number.
An offspring with a phenotype that matches one of the true-breeding parental (P generation) phenotypes