Chaper 15 Vocab Flashcards
Barr body
A dense object lying along the inside of the nuclear envelope in cells of female mammals, representing a highly condensed, inactive X chromosome
Sex linked gene
A gene located on a sex chromosome, resulting in a distinctive pattern of inheritance
Linked genes
Genes located close enough together on s chromosome that they tend to be inherited together
Genetic recombination
General term for the production of offspring with combinations of traits that differ from those found in either parent
Crossing over
The reciprocal exchange of genetic material between nonsister chromatids during prophase 1 of meiosis
Genetic map
An ordered List of genetic loci along a chromosome
Linkage map
A genetic map based on the frequencies of recombination between markers during crossing over of homologous chromosomes
Map units
A unit of measurement of the distance between genes.
Nondisjunction
An error in meiosis or mitosis in which members of a pair of homologous chromosomes or a pair of sister chromatids girl to separate properly from eachother
Polyploidy
A chromosomal alteration in which the organism possesses more than 2 complete chromosome sets.
Inversion
An aberration in chromosome structure resulting from reattachment of a chromosomal fragment in a reverse orientation to the chromosome from which it originated
Down syndrome
A human genetic disease caused by the presence of an extra chromosome, 21: characterized by mental retardation and heart and respiratory defects
Hemophilia
A human genetic disease caused by a sex linked recessive allele resulting in the a sense of one or more blood clotting proteins.
Genomic imprinting
A phenomenon in which expression of an allele in offspring depends on whether the allele is inherited from the male or female parent
