9 EXTRACHROMOSOMAL INHERITANCE

Question 1

Extrachromosomal inheritance also known as?

Answer 1

cytoplasmic inheritance or extranuclear inheritance

Question 2

• the inheritance of traits that are not controlled by chromosome genes

Answer 2

extrachromosomal inheritance

• this form of inheritance occurs in the cytoplasm of cells and involves genes present in cytoplasmic organelles

Question 3

• the extrachromosomal hereditary factors have the ability to____ and can be transmitted sexually or asexually

Answer 3

self-replicate

Question 4

extrachromosomal inheritance is discovered by?

Answer 4

Boris Ephrussi

Question 5

Criteria of Extrachromosomal Inheritance

• ____ follow the typical Mendelian Inheritance pattern
• inheritance of extrachromosomal factors is ____ of genes located within the cell nucleus
• in some cases, extrachromosomal traits are inherited exclusively from the ____.
• extrachromosomal inheritance can lead to characteristic phenotypic changes that are not inherited in a Mendelian pattern
• extrachromosomal genes can exhibit ____ which is rare in nuclear genes

Answer 5

does not
independent
mother
(This is because the egg contributes more cytoplasm to the zygote compared to the male parent)
vegetative (somatic) segregation
(random distribution of cytoplasmic elements during cell division in asexual reproduction)

Question 6

types of exrachromosomal inheritance

Answer 6

chloroplast inheritance
mitochondrial inheritance

Question 7

Possesses own DNA of chloroplast and mitochondria is called

Answer 7

cpDNA
mtDNA

Question 8

who discovered chloroplast inheritance

Answer 8

Carl Correns and Erwin Baur in 1909

Question 9

Correns conducted a study on?

and how?

Answer 9

Mirabilis jalapa (four o’clock)

he observed that the transmission of leaf color was strictly maternal, determined by the color of the ovule’s source

Question 10

Baur experimented on?

and how?

Answer 10

geranium
(Pelargonium zonale)

chloroplast genes can also be inherited from both parents or from the male parent only, resulting in variegated plants

Question 11

• Recent research conducted at the Max Planck Institute of Molecular Plant Physiology with ____ plants presents new evidence that challenges the commonly held belief that chloroplasts are solely inherited from the mother plant

Answer 11

tobacco

Question 12

• The researchers discovered that ____, chloroplasts from the father can also be passed on to the offspring

Answer 12

under specific environmental conditions

Question 13

mtDNA is main form of EI in?

Answer 13

animals

Question 14

2 characteristics of mtDNA

Answer 14

1. circular and
2. encodes 37 genes on 16.5kb of DNA

kb - kilobase

Question 15

who discovered mtDNA?

Answer 15

Margit and Sylvan Nass 1963

Question 16

• Mitochondria are primarily inherited ____

Answer 16

uniparentally, mostly maternally.

The zygote receives mitochondria exclusively from the mother, while the paternal contribution of mitochondria is minimal or negligible

Question 17

In biparental inheritance (mtDNA), children can inherit mtDNA from their fathers by?

Answer 17

mitochondrial DNA fragments can migrate into the nucleus and integrate with the chromosomes

• These mitochondrial DNA fragments are inherited alongside the nuclear chromosomes but the primary inheritance of mitochondrial DNA still occurs from the mother

Question 18

• Mode of inheritance where genetic material or traits are inherited from a single parent, either the mother or the father

Answer 18

Uniparental Inheritance

Question 19

• The genomes of extrachromosomal organelles are maternally inherited in most ____

Answer 19

eukaryotes

Question 20

example of uniparental inheritance

Answer 20

• Carl Correns’ experiments with four o’clock plants also demonstrated uniparental inheritance of chloroplast DNA, specifically through the maternal parent

Question 21

• Less common form of extrachromosomal inheritance where genetic material from both parents contributes to the traits encoded by the extrachromosomal organelles

Answer 21

Biparental Inheritance

Question 22

example of biparental inheritance

Answer 22

• Baur, 1909, observed the inheritance of leaf phenotypes in Pelargonium cultivars, describing the transmission of chloroplasts through biparental inheritance

Question 23

• Involves the random distribution of cytoplasmic elements during cell division in asexual reproduction

Answer 23

vegetative segregation

Question 24

in vegetative segregation, extrachromosomal DNA within the cytoplasm is ____ into daughter cells, resulting in ____ distribution of cytoplasmic content

Answer 24

randomly segregated
unequal

Question 25

5 Significance of Extrachromosomal Inheritance

Answer 25

1. Understand Evolutionary process
2. Trace maternal lineages
3. Understand inherited disorders
4. Forensic identification (act as fingerprint for ID purposes)
5. Mapping cp and mt genomes

Question 26

4 Challenges in Studying Extrachromosomal Inheritance

Answer 26

1. Studying inheritance pattern
2. Complexity of EI
3. Exact characteristics and components are unclear
4. Extrachromosomal hereditary factors could be lost through selection