AP BIOLOGY

Detailed explanation-1: -Often, these alterations happen due to errors during cell division when chromosomes align (Figure 1). Homologous recombination between areas of concentrated repeated sequences frequently creates deletions and duplications.

Detailed explanation-2: -A duplication is caused by the gain of a copy of a chromosomal segment at the original location on the chromosome. Duplications may be in an inverted orientation or in the original (direct) orientation. Other structural chromosome abnormalities do not result in gain or loss of any genetic material.

Detailed explanation-3: -One example of a rare genetic disorder of duplication is called Pallister Killian syndrome, where part of the #12 chromosome is duplicated.

Detailed explanation-4: -In meiosis, the chromosomes duplicate (during interphase) and homologous chromosomes exchange genetic information (chromosomal crossover) during the first division, called meiosis I. The daughter cells divide again in meiosis II, splitting up sister chromatids to form haploid gametes.