- genotype of female parent determines phenotype of offspring

Infectious Heredity: symbiotic or parasitic association of microorganisms with eukaryotic cells

Maternal Effect: - products stored in the egg prior to fertilization (proteins or untranslated mRNAs)

- genotype of female parent determines phenotype of offspring

- amino acid tryptophan is precursor of kynurenine which is precursor of pigment

- kynurenine or an associated enzyme is synthesized in oocytes with a least one A allele prior to completion of meiosis

- consequently, larva which are aa but received one mutant allele derived from an Aa oocyte (female parent's genotype) will be pigmented

- effects of pigmentation decline in larva as it grows (diluted) and adult has red eyes and minimal body pigment associated with the aa genotype when the female parent was aa.

- snail, Limnaea peregra, shell coiling (Fig. 8.2)

- orientation of spindle determines direction of coiling

- orientation of spindle affected by specific gene product associated with dextral allele (D-) which accumulates in the oocyte cytoplasm prior to completion of meiosis; dd results in no gene product

- consequently, offspring's phenotype depends on maternal parent's genotype

Chloroplast and mitochondria have own genomes and replicate independently of nuclear DNA but the function of the organelles depends on both nuclear and organelle DNA!

- 4 o'clock plant, Mirabilis jalapa, leaf color

- inheritance of leaf color is strictly maternal

- leaf color on branch that produces seeds determines progeny's color (e.g., green leafed branch -- green leafed progeny; white leafed branch -- white leafed progeny; variegated branch -- green, white or variegated leafed progeny)

- Iojap on Maize (Fig. 8.3)

- leaf color influenced by both a nuclear gene (wild type Ij) and products stored in the cytoplasm

- nuclear gene affects chloroplasts which are then transmitted via the egg cytoplasm

Mitochondria Inheritance:

- mold, Neurospora crassa, growth rates

- slow growth strain, POKY, a suppressive mutation, is inherited maternally

- yeast, Saccharomyces, growth patterns (petite) Fig. 8.4

- petite phenotype arises at least three different ways; a nuclear mutation which is inherited in Mendelian patterns; a neutral mutation (caused by deletions in mtDNA) which prevents the formation or replication of mitochondria; and the suppressive petites (also caused by deletions) which behave like the POKY in Neurospora, i.e., the mutant behaves dominantly.

MERRF, myoclonic epilepsy and ragged red fiber disease

- mutation in one of the tRNA genes; affects both muscles fibers and mitochondria are abnormal in appearance

- express deafness and dementia plus seizures

- caused by four different mutations (usually in subunit of NADH dehydrogenase) which disrupt normal oxidative phosphorylation

- individuals suffer sudden bilateral blindness

- associated with loss of sight and hearing and various heart conditions

- caused by various deletions with mtDNA

- symptoms may be delayed until adulthood; severity correlated to number of deletions

Kappa in Paramecium
Infective particles in Drosophila