Structural Aberrations: Inversions

Question 1

This results from two chromosomal breaks with inversion through 180° of the segment between the breaks.

Answer 1

Inversions

Question 2

In this type of inversions, the breaks are on either side of the centromere and it is included in the inversion.

Answer 2

Pericentric inversion

Question 3

In this type of inversions, the breaks are in a single arm, and the centromere is not included in the inversion.

Answer 3

Paracentric inversion

Question 3

In chromosomes with inversion, homologous pairing usually required that one member form a ____ in the region of the inversion.

Answer 3

loop.

Question 3

T/F. Inversions interfere with the pairing of homologous chromosomes during meiosis, and crossing-over tends to be suppressed within the inverted segment.

Answer 3

True.

Question 3

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

Answer 3

True

Question 4

For a paracentric inversion, if a cross-over does occur within the loop, then this will result in a ____ and an ____ fragment.

Answer 4

dicentric chromatid; acentric

Question 5

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

Answer 5

uneven number; deletion; duplication

Question 6

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.

Answer 6

True.

Question 7

In contrast to inversions, _____ involves no change in gene order and little consequence to offspring.

Answer 7

centromere repositioning