This document discusses various types of chromosomal abnormalities including aneuploidy which is having an extra or missing chromosome, euploidy which is having a complete set of chromosomes, and polyploidy which is having more than two sets of chromosomes. It also discusses how fetal cells can be obtained from amniotic fluid or the chorion of the placenta and how polyploidy can originate from the addition of extra chromosome sets or the combination of chromosome sets from different species. Monosomy where a single copy of a recessive gene is present may be insufficient to provide life-sustaining functions.

5.  Aneuploidy
› Gain or loss, one or more chromosomes
› Monosomy, Trisomy
 Euploidy
› Complete haploid sets
 Polyploidy
› More than two sets are present

8.  A single copy of a recessive gene (due to
monosomy) may be insufficient to provide
life-sustaining functions

14.  Fetal cells obtained from amniotic fluid

15.  Fetal cells obtained from the chorion of the
placenta

16.  Fetal cells and DNA are derived directly from
maternal circulation

22.  Originates in two ways:
 1. the addition of one or more extra sets of
chromosomes, identical to the normal
haploid complement of the same species,
resulting in autopolyploidy
 2. the combination of chromosome sets from
different species occurring as a
consequence of hybridization, resulting in
allopolyploidy

29.  Also called a deficiency
 A chromosome breaks in one or more places
and a portion is lost

30.  Terminal deletions
 Intercalary deletions

31.  Loss of a small part of the short arm of
chromosome 5

32.  A piece of the chromosome is present more
than once in the genome

34.  1. may result from gene
redundancy
 2. may produce
phenotypic variation
 3. have been an
important source of
genetic variability
during evolution

35.  rDNA codes for RNA segments
 Gene amplification occurs when multiple
copies of gene code for a specific product

38.  A segment of the chromosome if turned
around 180 degrees within the same
chromosome

41.  The movement of a
chromosomal
segment to a new
location in the
genome

45.  Appear as gaps in some karyotypes
 Appear to be susceptible to breakage in
some situations

46.  Chromosome 16, WWOX gene
› Lung, breast, ovary, prostate, bladder,
esophagus, pancreas
 Chromosome 3, FHIT gene
› Esophagus, breast, cervix, liver, kidney,
pancreas, colon, stomach
 Increased susceptibility to mutations and
deletions