Structural Aberrations: Inversions Flashcards
This results from two chromosomal breaks with inversion through 180° of the segment between the breaks.
Inversions
In this type of inversions, the breaks are on either side of the centromere and it is included in the inversion.
Pericentric inversion
In this type of inversions, the breaks are in a single arm, and the centromere is not included in the inversion.
Paracentric inversion
In chromosomes with inversion, homologous pairing usually required that one member form a ____ in the region of the inversion.
loop.
T/F. Inversions interfere with the pairing of homologous chromosomes during meiosis, and crossing-over tends to be suppressed within the inverted segment.
True.
T/F. Generally, inversions causing change in gene order does not produce clinical abnormality. The medical significance lies with the increased risk of generating unbalanced gametes
True
For a paracentric inversion, if a cross-over does occur within the loop, then this will result in a ____ and an ____ fragment.
dicentric chromatid; acentric
In contrast, for a pericentric inversion, if an ____ number of cross-overs occurs within the loop, then each of the two chromatids produced will have both a ____ and a ____, and abnormal offspring may be produced
uneven number; deletion; duplication
T/F. In inversions, the closer both breakpoints are to the telomeres, the smaller the duplication and deletion and thus the higher the likelihood of survival of the fetus until birth.
True.
In contrast to inversions, _____ involves no change in gene order and little consequence to offspring.
centromere repositioning