Polyploidy and Organellar Genetics Flashcards

Flashcards for BIOL 2301 Genetics and Molecular Biology lecture notes on Polyploidy and organellar genetics.

Chromosome Re-arrangements During Evolution

During evolution, the different chromosomes must have exchanged DNA, leading to chromosome re-arrangements when comparing mouse and human chromosome sequences.

Chromosome Separation in Meiosis 1

There are three different ways that the chromosomes can be separated during meiosis one, depending on which centromere/kinetochore the spindle fibers attach.

Balanced Gametes

Balanced gametes are needed for survival, meaning each part of the chromosomes should be present exactly once.

Robertsonian Translocation

A special case of nonreciprocal translocation involving the fusion of two acrocentric chromosomes in the centromere region, resulting in the apparent loss of one chromosome in karyotype analysis.

Robertsonian Translocation and Down Syndrome

When chromosome 21 is involved in a Robertsonian translocation, it can lead to an inherited type of Down syndrome.

Euploid

Cells with complete sets of chromosomes.

Aneuploidy

Describes the loss of a chromosome or the gain of an additional chromosome.

Monosomy

A form of aneuploidy in diploids where an individual is missing one chromosome.

Trisomy

A form of aneuploidy in diploids where an individual has an extra chromosome present in addition to the two complete sets.

Turner Syndrome

Females who are XO; the phenotype includes unusually short stature and sterility due to lower-than-normal doses of X-linked genes.

Klinefelter Syndrome

Males with more than one X chromosome (typically XXY); the phenotype includes unusually tall stature and sterility due to abnormally high X-linked gene dosages.

Meiotic Nondisjunction

The failure of homologs to separate during meiosis I, or the failure of sister chromatids to separate during meiosis II, resulting in aneuploid meiotic products.

Trivalent

Abnormal pairing of trisomic chromosomes in cell division.

Univalent

Extra chromosome in trisomy is unpaired in cell division.

n

The number of chromosomes in the gamete.

x

The number of chromosomes in a single, complete set.

Basic Chromosome Number (x)

The number of chromosomes that constitute a complete set; In diploids, x = n, where n is the number of chromosomes in gametes.

Monoploid plants

Geneticists can use haploid pollen and induce the growth of a plant by treating the embryoids with plant hormones and nutrients

Colchicine

Prevents the formation of the spindle apparatus; therefore, microtubules are not connected to the kinetochore of chromosomes and are not transported to the opposite sides of the cell.

Autopolyploid

All chromosome sets are derived from the same species.

Allopolyploids

Usually sterile hybrids with complete chromosome sets from different, though related, species.

Chloroplasts

Plant organelles that capture solar energy and store it in the chemical bonds of carbohydrates through the process of photosynthesis.

Heteroplasmic cells

Cells contain a mixture of organelle genomes

Homoplasmic cells

Cells contain only one type of organelle genome.

Mitochondria

Organelles that convert energy derived from nutrient molecules into ATP via the process of oxidative phosphorylation.

Endosymbiont Theory

Mitochondria and chloroplasts are descended from bacteria that fused with nucleated cells.