B chromosomes

Definition

Extra, non-essential chromosomes found in some species of plants and animals, often associated with various genetic effects, including altered traits and fertility.

Etymology

Named after their secondary nature, as they are not part of the standard chromosome set.

Example

In some populations of Nasonia vitripennis wasps, B chromosomes can cause a condition called paternal sex ratio (PSR).

Related Terms

• Heterochromatin
• Supernumerary chromosomes
• Paternal sex ratio
• Genetic variation

Usage Notes

B chromosomes can vary in size and number between individuals and populations. Their presence and effects can be influenced by factors like environmental stress.