Extranuclear inheritance involves the transmission of genetic information outside the nucleus, primarily through mitochondrial and chloroplast DNA. This non-Mendelian inheritance is key in understanding genetic disorders, maternal lineage, and evolutionary biology. It includes maternal inheritance of mitochondrial DNA, horizontal transmission of extranuclear genomes, and various inheritance patterns such as vegetative segregation, uniparental, and biparental inheritance. The study of mitochondrial mutations further illuminates the impact of extranuclear DNA on phenotypic variations and hereditary diseases.
Show More
Extranuclear inheritance is the transmission of genetic information through cellular components outside the nucleus
DNA in Organelles
Extranuclear inheritance primarily involves the DNA contained within organelles such as mitochondria and chloroplasts
Differences from Nuclear DNA
Unlike nuclear DNA, extranuclear DNA replicates independently and often does not follow the Mendelian inheritance pattern
Understanding extranuclear inheritance is crucial for understanding certain genetic disorders and the evolutionary history of species
Mitochondrial inheritance is a classic example of extranuclear inheritance, characterized by the transmission of mitochondria from the mother to the offspring
During fertilization, the egg contributes the majority of the cytoplasm to the zygote, while the sperm contributes primarily nuclear DNA
The maternal lineage of mitochondrial DNA is significant for tracing genetic diseases and studying maternal ancestry in populations
Extranuclear inheritance also encompasses the horizontal transmission of genetic material from viruses and symbiotic bacteria
Viruses can transmit their genetic material to offspring, resulting in congenital infections
Symbiotic bacteria, such as Wolbachia in insects, can be passed from mother to offspring, affecting the host's reproduction and evolution
Extranuclear inheritance can be categorized into three types: vegetative segregation, uniparental inheritance, and biparental inheritance
Vegetative segregation refers to the stochastic distribution of organelles during cell division, leading to a variable number of organelles in daughter cells
Uniparental inheritance occurs when only one parent contributes the organelle's genetic material, while biparental inheritance involves contributions from both parents
00
The DNA within ______ and ______ is primarily involved in extranuclear inheritance.
mitochondria
chloroplasts
01
Mitochondrial DNA is often inherited from a single parent, typically the ______.
mother
02
Definition of mitochondrial inheritance
Transmission of mitochondria and their DNA from mother to offspring, bypassing paternal mitochondrial DNA.
