Eukaryotic Chromosome and Transposable Elements

These flashcards cover key concepts related to eukaryotic chromosomes, chromosomal variations, and transposable elements for Exam 3.

What is the main difference between euchromatin and heterochromatin?

Euchromatin is less condensed, has higher gene density, and is easier to transcribe, while heterochromatin is more condensed, has higher repeat content, and is harder to transcribe.

What is ATAC-Seq used for?

ATAC-Seq is used to detect open chromatin accessibility.

What are the two types of heterochromatin?

Constitutive heterochromatin (always condensed) and facultative heterochromatin (sometimes condensed).

How can chromosomal abnormalities be visualized?

Chromosomal abnormalities can be visualized through cytogenetics techniques such as high-resolution G-banding and fluorescent in situ hybridization (FISH).

What happens during aberrant crossing-over?

Aberrant crossing-over can cause deletions, duplications, and inversions of chromosomal regions.

What is the outcome of histone acetylation?

Histone acetylation leads to unpacking of the chromosome, making it more accessible for transcription.

Describe the consequences of pericentric inversion.

The consequences of pericentric inversion depend on the relationship of the inversion with the centromere, potentially leading to abnormal chromosomal outcomes during gamete formation.

What is Position-Effect Variegation (PEV)?

PEV is a genetic phenomenon where the position of a gene within the genome affects its expression, as seen with the white gene in Drosophila.

What are the two classes of transposable elements (TEs)?

Class I: Retrotransposons (copy-and-paste via RNA intermediate); Class II: DNA Transposons (cut-and-paste mechanism).

How do retrotransposons move through an RNA intermediate?

Retrotransposons first transcribe their DNA into RNA, then reverse transcribe it back into DNA before inserting into the genome.