21- Nonmendelian Genetics

What would be the result if this F2 generation is allowed to self?

....

The ______ form confers "Killer" specificity... they secrete toxins that kill cells without the particle... thus eliminating competition for resources! There are many other examples of less obvious utility... Mu particles for instance, which are mate killers!

B form

with bateriophages

B form

The pathogenic effect of ________ disease is displayed here... progressive vacuolization and eventual loss of neurons in the brain producing a descriptively named "________ ________-."

Creutzfeldt-Jakob; spongiform encephalopathy

Have you ever noticed the different phenotypes displayed by the same species of plants grown in different environments? ________ trees are a good example... down in the bayou, they look like this.. In the high dry soil in front of the Chemistry building, they are totally different. The same with elephant ear plants... in the shade... huge, in bright sun... small. The white oak leaves on the next slide demonstrate a similar pattern.

Cyprus

______ is often referred to as "tightly coiled" ... in any case, genes are turned off.

Heterochromatin

How do the organism get in heterochromatin form? Two primary processes can be involved.

Histone deacetylation and nucleotide (usually cytosine) methylation.

Infective Inclusions: Paramecium, may or may not, for instance possess "_______" particles, clearly bacterial endosymbionts, which may in turn possess viral endosymbionts.

Kappa

each cell has one and it controls cell maintenance functions; control cell activities; housekeeping organs

Macronucleus (paramecium)

prokaryotic type genome, circular DNA, maternal inheritance

Mitochondria

_______ undergo spiral cleavage, with each early layer of mitotically produced blastomeres rotating ~45 degrees, either to the left or the right, based upon the maternal effect gene product provided by the mother snail.

Mollusks

without bateriophages

N form

kappa particles come in two types

N form and B form

the process through which a methyl group is added to DNA nucleotides.

Nucleotide Methylationis

There are normal, endogenous "prion" proteins, _____, the function(s) of which is uncertain. It is highly conserved across mammalian species, however, suggesting a critical importance. Most of the studies, not surprisingly, indicate protection from various ________ diseases, including, but not limited to CJD/scrapie. Others have suggested roles in ________ formation, _______ transmission, and various _______-metabolic functioning.

PrPc neurodegenerative; memory, synaptic, neuro

The diseases are progressive, as newly produced ______ proteins recruit more and more of the same.

PrPsc

There exists a pathogenic version, _____, which can alter the form of the normal version into a similar pathogenic version. Note that the actual gene sequence is not modified... these changes are entirely _________ The condition in humans is called Creutzfeldt-Jakob disease, in sheep, it is known as "_______-." The diseases are progressive, as newly produced PrPsc proteins recruit more and more of the same.

PrPsc post-translational. scrapie (flanks of wool will be scraped up because of their weird behavior)

Other organisms, especially among the _______, contain an array of similar endosymbiotic organelles with expressible genes, controlling traits displayed by the cells that contain them! As a group, they are referred to as "________ _______."

Protista; infective inclusions

Conrad _______ (1930's), noticed that certain genes involved in embryonic development were permanently "turned _____" after they acted; realized if u turn off genes you turn off gene development We know this very well today, and it's a good thing they are "turned off" ... when they accidentally come back on it can spell trouble (cancer).

Waddington; off

What the maternal effect gene product does, in this case, is establish the very early embryonic direction of ______ _______.

cell cleavage

prokaryotic, maternal inheritance, pigmentation and resistance

chloroplasts

______ ______ involves a wide array of non-nuclear genes

cytoplasmic inheritance

maternal effects of Limnaea sp.

dextral vs sinistral shell coiling

________ or right-handed snails, at least in the aquatic genus Limnaea, are the wild type, so dextral is the _______- allele

dextral; dominant

a smaller organism that lives within another organism, the theory of how eukaryotic cells were formed; a theory that states that certain kinds of prokaryotes began living inside of larger cells and evolved into the organelles of modern-day eukaryotes;

endosymbiotic

______ _______ relate to things affecting the phenotype other than, or in cooperation with the underlying DNA sequence

epigenetic effects

Heritable modification of gene function without a change in the DNA sequence. In this sense, "heritable" does not necessarily mean heritable from one generation of organisms to the next, but rather refers to successive generations of cells.

epigenetics

A good epigenetics example is seen in "chromatin remodeling" ...

euchromatin vs heterochromatin

Limnaea sp. are also self _______, and so, in a lab, they can be "selfed." When the sinistrally coiled, heterozygous snail is selfed, all of its offspring are ________... even the homozygous recessive... because of their mother's genotype, not their own genotypes.

fertile; dextral

There is a lot of overlap to the various "forces" that result in phenotypic expression. Certainly, our _______ are foremost in this regard, but a wide array of ________ and _________ influences can play roles as well... there are obvious results of nutrient poor diets, maternal consumption of alcohol (and other toxins) during pregnancy. Things are never a simple as they might seem in biology. So many stochastic influences!

genomes; epigenetic; environmental

Note, on the left, that when the "female" is homozygous dominant and the "male" is homozygous recessive, the offspring, as expected, will be ________. They will also display the dominant phenotype, but, we shall see, it's not because they are expressing their own genotype! Remember, this is a "________ effect" situation so the gene products causing the dextral right-handedness came from the mother, not the snail displaying the phenotype!

heterozygous; maternal

deacetylated histones which stops transcription; removes acetyl groups from histone tails, causing the histones to wrap more tightly around the DNA and interfering with the transcription of genes by blocking access by transcription factors;

histone deacetylation

many types, mostly prokaryotic/viral

infective inclusions

This is pretty clear in the mating on the right. The same parental homozygous genotypes are seen but this time it's the female that is homozygous recessive. The gene product she will pass on to their offspring will include the ________ that induces ________-handedness aka ________!

mRNA/protein; left; Sinistral

_________ in which the mother's genotype influences phenotype of offspring

maternal effects

There are (at least) three broad, non-mutually exclusive categories:

maternal effects, cytoplasmic inheritance, epigenetic effects

These are mitochondia associated conditions: They are ________ inherited and often relate to oxidative _______ pathways. Consider that the function of mitochondria is to produce _____ levels necessary for normal eukaryotic function. Disruption of those pathways can result in a wide array of _______ with mild, moderate, or severe consequences.

maternally; metabolic ATP; disorders

essential for genetic recombination; controls reproduction

micronucleus (paramecium)

various things inside cells that are not human cells that play a role in cytoplasmic inheritance

mitochondria, chloroplasts, and infective inclusion

_________ and _________ are endosymbiotic bacteria with their own genomes.

mitochondria; chloroplasts

Limnaea sp. are ________, and if an investigator then breeds dextral and sinistral snails together, the results then depend on which _______ provides the eggs and which the sperm!

monoecious (self-fertile); individual

is a broad description of phenotypic expression that fails to follow discernible Mendelian distributions

non-mendelian

Another epigenetic manifestation is related to the formation of infectious _____-.

prions

infectious forms of "normal" proteins that catalytically modify other "normal" forms of the same type of infectious state

prions

Certain structural characteristics in _______, including the distribution of _______ structures in dividing ciliates are inherited w/o recourse to the DNA. The mechanism is not well understood.

protists; ciliary

Just like Mendel did with his pea plants, it is easy to establish true-breeding populations of snails in separate aquaria, so that one tank has all right-handed snails and the other, "________" or left-handed

sinistral

not expressing its own geneotype, but expressing the moms genotyple

sinistral