Chapter 15 - Chromosomal Basis of Inheritance Flashcards
A basic principle in biology stating that genes are located at specific locations (loci) on chromosomes and that the behavior of chromosomes during meiosis accounts for inheritance patterns
Chromosome Theory of Inheritance
The phenotype most commonly observed in natural populations; also refers to the individual with that phenotype
Wild Type
A gene located on either sex chromosome. Most of these genes are on the X chromosome and show distinctive patterns of inheritance; there are very few genes on the Y chromosome
Sex-Linked Gene
A gene located on the X chromosome; such genes show a distinctive pattern of inheritance
X-linked gene
A human genetic disorder caused by a sex-link recessive allele; characterized by progressive weakening and a loss of muscle tissue
Duchenne Muscular Dystrophy
A human genetic disease caused by a sex-linked recessive allele resulting in the absence of one or more blood-clotting proteins; characterized by excessive bleeding following injury
Hemophilia
A dense object lying along the inside of the nuclear envelope in the cells of female mammals, representing a highly condensed, inactivated X chromosome
Barr Body
Genes located close enough together on a chromosome that they tend to be inherited together
Linked genes
General term for the production of offspring with combinations of traits that differ from those found in either parent
Genetic recombination
An offspring with a phenotype that matches one of the true-breeding parental (P generation) phenotypes; also refers to the phenotype itself
Parental types
An offspring whose phenotype differs from that of the true-breeding P generation parents; also refers to the phenotype itself
Recombinant types/recombinants
The reciprocal exchange of genetic material between nonsister chromatids during prophase 1 of meiosis
Crossing over
An ordered list of genetic loci (genes or other genetic markers) along a chromosome
Genetic map
A genetic map based on the frequencies of recombination between markers during crossing over of homologous chromosomes
Linkage map
A unit of measurement of the distance between genes. One of these is equivalent to 1% recombination frequency
Map units
An error in meiosis or mitosis in which members of a pair of homologs or a pair of sister chromatids fail to separate properly from each other
Nondisjunction
A chromosomal aberration in which one or more chromosomes are present in extra copies or are deficient in number
Aneuploidy
Referring to a diploid cell that has only one copy of a particular chromosome instead of the normal two
Monosomic
Referring to a diploid cell that has three copies of a particular chromosome instead of the normal two
Trisomic
A chromosomal alteration in which the organism possesses more than 2 complete chromosome sets. It is the result of an accident of cell division.
Polyploidy
A deficiency in a chromosome resulting from the loss of a fragment through breakage; a mutational loss of one or more nucleotide pairs from a gene
Deletion
An aberration in chromosome structure due to fusion with a fragment from a homolog, such that a portion of a chromosome is duplicated
Duplication
An aberration in chromosome structure resulting from reattachment of a chromosomal fragment in a reverse orientation to the chromosome from which it originated
Inversion
An aberration in chromosome structure resulting from attachment of a chromosomal fragment to a nonhomologous chromosome
Translocation
A human genetic disease 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
Down Syndrome
A phenomenon in which expression of an allele in offspring depends on whether the allele is inherited from the male or female parent
Genetic imprinting
