Chapter 1-7: Introduction to Chromosomal Variations

Flashcards covering key vocabulary and concepts from the lecture on chromosomal variations, duplications, inversions, translocations, and ploidy changes.

Karyotype

A photographic layout of all the chromosomes.

Paralogs

Extra genes that come from a duplication.

Gene family

A group of related genes, often formed from duplications, such as the globin genes.

Fetal hemoglobin

A type of hemoglobin that allows for differential hemoglobin expression at different stages in the body, essential for placental birth with internal development.

p53

A gene largely associated with fighting cancer.

p63

A gene that is a paralog of p53, studied to understand its roles, often in the context of cancer-fighting properties.

Copy number variation

Small segments of DNA getting duplicated or deleted, meaning individuals may have different numbers of the same gene, often resulting from uneven crossing over.

Inversion

A chromosomal rearrangement where a segment of a chromosome flips and reattaches backwards, changing the order of genes without creating or losing genetic material.

Pericentric inversion

An inversion that includes the centromere, meaning the inverted segment surrounds the centromere.

Paracentric inversion

An inversion that does not include the centromere, occurring to one side of the centromere.

Breakpoint effect

The instance when an inversion or other chromosomal rearrangement happens to break up an important gene.

Position effect

The phenomenon where the location of a gene on a chromosome affects its expression; an inversion can move a gene to a low or high expression spot, changing its phenotype.

Reciprocal translocation / Balanced translocation

A type of translocation where parts of two different chromosomes are exchanged, but all genetic material is still present and can be found in the genome.

Simple translocation

A type of translocation where a piece of a chromosome is found extra somewhere else, while the original chromosome may still have a normal copy.

Translocation

A chromosomal rearrangement involving the movement of a gene or segment of a chromosome to a non-homologous chromosome, such as the alpha and beta globin genes ending up on different chromosomes.

Down syndrome

A condition normally resulting from an extra chromosome 21 (trisomy 21), generally a one-time error in meiosis and not inheritable.

Familial Down syndrome

A form of Down syndrome caused by a translocation, typically a large piece of chromosome 21 stuck onto chromosome 14, making it inheritable within families.

Euploidy

A variation in chromosome number involving changes in entire sets of chromosomes.

Aneuploidy

A variation in chromosome number involving a change in the number of a particular chromosome (having an extra or missing one).

Diploid

Having two copies of each chromosome.

Haploid

Having half copies of chromosomes, typically one copy.

Monoploidy

Having a single set of chromosomes.

Triploidy

A euploidy variation where an organism has three complete sets of chromosomes.

Tetraploidy

A euploidy variation where an organism has four complete sets of chromosomes.

Ploidy

Refers to variations in the number of entire sets of chromosomes.

Somy

Refers to variations in the number of a single chromosome, either missing or duplicated.

Trisomy

Having three copies of a particular single chromosome, such as trisomy 21.

Monosomy

Having only one copy of a particular single chromosome, such as monosomy at 21 or 23 (sex chromosome).

Cope's rag gray tree feathers

A group of gray tree frogs, including versicolor (tetraploid, North) and chrysalis (diploid, South), that are physically identical but genetically incompatible, distinguished by their call trill rates.

versicolor (Cope's rag gray tree feathers)

The tetraploid form of Cope's rag gray tree feathers, found in the North, distinguished from chrysalis by its faster call trill rate.

chrysalis (Cope's rag gray tree feathers)

The diploid form of Cope's rag gray tree feathers, found in the South, distinguished from versicolor by its slower call trill rate.

Spermatophore

A little packet of sperm laid on the ground by male salamanders, which females pick up.

Kleptoparasitism (genome building)

A process, named by Jim Bogart, where organisms randomly pick up and drop genomes, leading to changes in ploidy number, observed in salamanders.