1

Non-Mendelian Inheritance

Extranuclear genes

Mitochondria

Chloroplasts

Epigenetic phenomenon

Impacts expression of genes or development

2

Mitochondrial Inheritance

Maternal inheritance in most organisms - cytoplasmic donor

Mitochondrial Eve - common African ancestor > 150,000 years ago

3

Mitochondrial Mutations in Humans

Many diseases associated with defects in mitochondria

Some alsocaused by nuclear genes

4

Maternal Inheritance in Neurospora

Poky mutants - defective cytochromes in mitochondria

Phenotype of mother appears in all offspring

5

Transmission of Chloroplasts

Plants often uniparental inheritance

Angiosperms (flowering)

Most maternal inheritance

Some from both (biparental)

Few mostly paternal (evening primrose)

Conifers (gymnosperms)

Mostly paternal inheritance

6

Transmission of Chloroplasts

Shoot color in four o’clock plants - variegation

7

Transmission of Chloroplasts

Shoot color in four o’clock plants - maternal inheritance

8

Transmission of Chloroplasts

Variegation due to heteroplasmy

9

Petite Mutations in Yeast

Nuclear Inheritance Uniparental inheritance of mitochondria

10

Infectious Heredity

Microorganisms coexist symbiotically with host

Killer phenomenon in yeast

toxin

L helps M replicate

11

Maternal Effect

Mother’s genotype determines phenotype of progeny

Shell coiling in snails

12

Maternal Effect

Hermaphrodites

D- mother

dextral offspring

dd mother

sinistral offspring