Chapter 3 part 2 Flashcards
Deletion
A type of chromosomal aberration or mutation at the DNA level in which there is a loss of part of a chromosome or of one or more nucleotides
Interstitial Deletion
Deletion that occurs from the interior of a chromosome
Terminal deletion
A deletion that occurs toward the end of a chromosome
Duplication
A segment of DNA that duplicated itself
Inversion
A change in direction of the genetic material along a single chromosome
Pericentric Inversion
A chromosome inversion that includes the centromere
Paracentric Inversion
A chromosomal inversion that does not include the centromere
Inversion loop
A structure formed in meiosis I by a chromosome with either a paracentric or pericentric inversion
Translocation
A segment of one chromosome becomes attached to a different chromosome(not a normal event)
Reciprocal Translocation
Two non-homologous chromosomes exchange genetic material
rearrangement of genetic material, not change in total amount
Balanced Translocation
If there is the same amount of genetic material after reciprocal translocation
Unbalanced Translocation
If there is genetic material missing, or transfer of genetic material occurs in only one direction after translocation
Robersonian Translocation
Translocation between two acrocentric chromosomes
Translocation cross
Must form for the translocated chromosome to synapse properly
Alternate segregation
at meiosis in reciprocal translocation heterozygote, the passage of both chromosomes to one pole and both translocated chromosomes to the other pole, giving genetically balanced gametes
Adjacent Translocation
Segregation of non-homologous chromosomes in a reciprocal translocation heterozygote such that unbalanced gametes with duplications and deficiencies are produced (horizontal divide)
Adjacent 2 segregation
segregation of homologous chromosomes during meiosis in a translocation heterozygote such that unbalanced gamete with duplication and deficiencies are produced (vertical divide)
Meiotic Non-disjunction
Failure of two members of a chromosome pair to separate from one another during meiosis, causing both chromosomes to go to a single daughter cell
Pseudodominant
The apparent dominant transmission of a disorder when an individual homozygous for a recessive gene has effected offspring through having children with an individual who is also a carrier
Describe some most commonly seen chromosome disorders caused by numerical as well as structural abnormalities
cri-du-chat syndrome
Wolf-Hirshhorn syndrome
Cri-du-chat syndrome
cry of young infants
heart defects
mental disability
Wolf-Hirshhorn syndrome
Abnormal facial features
mental disabilities, seizures
Slow growth and development
Caused by deletion of chromosome 4 in the short arm
