CLINICAL CYTOGENETICS QUESTIONS
WITH 100% CORRECT ANSWERS {
GRADED A+}
What describes the human nuclear genome? - ✔✔-the haploid set of
chromosome numbers
-22 autosomes and 1 sex chromosome (23 total)
-3 billion base pairs
-27,000 protein coding genes and 3,000 RNA coding genes
-biological complexity corresponds to the size of the non coding
genome
-transposons are the major non coding class
,X chromosome inactivation - ✔✔-process that occurs in female
mammals in which one of the X chromosomes is randomly turned off in
each cell
-only one of the X chromosomes is active
-explains calico cats
-prevents cells from getting twice as many gene products
-inactivated one is called the Barr body
-can be skewed (same one is inactivated) or random (different one is
inactivated)
Aneuploidy - ✔✔-Gain or loss of one chromosome
-can be autosomal or sex chromosome
Ex) Monosomy X (only viable monosomy)
, -Turner syndrome; produces X0 females, who are sterile; it is the only
known viable monosomy in humans
Polyploidy - ✔✔-Gain of one or more haploid sets of chromosomes
-Triploidy: three haploid sets of chromosomes total number is 69,
supposed to be 46. Common result is miscarriage
-Dispermy: caused by fertilization of one egg by two sperm
-Digyny: fertilization of diploid egg by haploid sperm
-Diandy: egg is fertilized by two sperm or by a diploid sperm
-Tetraploidy: two diploid sets of chromosomes. Total number is 92
Ex) Trisomies (XXX, XXY, XYY)
-Phenotypic burden increases with 4 or more X or Y chromosomes
-Tetrasomies (XXXX, XXXY, XXYY)
-Intellectual disabilities result
WITH 100% CORRECT ANSWERS {
GRADED A+}
What describes the human nuclear genome? - ✔✔-the haploid set of
chromosome numbers
-22 autosomes and 1 sex chromosome (23 total)
-3 billion base pairs
-27,000 protein coding genes and 3,000 RNA coding genes
-biological complexity corresponds to the size of the non coding
genome
-transposons are the major non coding class
,X chromosome inactivation - ✔✔-process that occurs in female
mammals in which one of the X chromosomes is randomly turned off in
each cell
-only one of the X chromosomes is active
-explains calico cats
-prevents cells from getting twice as many gene products
-inactivated one is called the Barr body
-can be skewed (same one is inactivated) or random (different one is
inactivated)
Aneuploidy - ✔✔-Gain or loss of one chromosome
-can be autosomal or sex chromosome
Ex) Monosomy X (only viable monosomy)
, -Turner syndrome; produces X0 females, who are sterile; it is the only
known viable monosomy in humans
Polyploidy - ✔✔-Gain of one or more haploid sets of chromosomes
-Triploidy: three haploid sets of chromosomes total number is 69,
supposed to be 46. Common result is miscarriage
-Dispermy: caused by fertilization of one egg by two sperm
-Digyny: fertilization of diploid egg by haploid sperm
-Diandy: egg is fertilized by two sperm or by a diploid sperm
-Tetraploidy: two diploid sets of chromosomes. Total number is 92
Ex) Trisomies (XXX, XXY, XYY)
-Phenotypic burden increases with 4 or more X or Y chromosomes
-Tetrasomies (XXXX, XXXY, XXYY)
-Intellectual disabilities result
