Bio 201 Exam 4

Aneuploidy

When an organism gains or loses a chromosome or two.

Monosomy

The loss of a single chromosome.

Trisomy

The gain of a single chromosome from a diploid genome.

Euploidy

When complete haploid sets of chromosomes are present.

Polyploidy

When more than two sets of chromosomes are present.

Down syndrome critical region

Contains dosage-sensitive genes.

Deletion

Involves getting rid of a portion of a chromosome.

Inversion

A segment of a chromosome is reversed end to end.

Translocations

Alter the location of genes within the genome.

Structural changes

Include deletions, duplications, inversions, and translocations.

Deletion (deficiency)

Involves a missing region of a chromosome.

Duplication

Involves a repeated segment of a chromosome.

Ribosomal RNA (rRNA)

Multiple copies of genes that encode for rRNA.

Inversions

A class of structural variation involving rearrangement of linear gene sequences.

Translocation

Involves pieces of chromosomes moving to new locations.

Reciprocal translocation

Exchange of segments between nonhomologous chromosomes.

Fragile sites

Regions of chromosomes susceptible to breakage.

Sex determination

Various mechanisms exist, including X and Y chromosome pairing during meiosis.

SRY gene

Encodes the TDF protein, critical for testes formation.

Lyon hypothesis

States that X chromosome inactivation is random in cells.