Test 3 - Mendelian Genetics And Inheritance Flashcards Preview

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Flashcards in Test 3 - Mendelian Genetics And Inheritance Deck (16):

What are Mendel’s 3 laws and describe them?

Law of segregation
—Factors for each trait segregate such that each gamete only carries one factor for each trait
—Basically, one allele comes from one parent and another comes from the second

Law of independent assortment
—Each factor that segregates does so independently

Law of dominance
—Some factors are dominant, some are recessive, and the dominant trait will always be expressed when present


What is an allele?

Different forms of a gene
—I.e. flower color is an allele


Relating to the law of independent assortment, the number of combinations therefore depends on what?

Number of alleles


Dominance does not imply superior or normality, but what?

Simply preferred expression

*They are not always the most common in a population, they can be rare


Genetic variability and selection are important, why?

Maintaining genetic adaptability to variable environmental factors

*Resistance to extinction

**Example - Bananas are basically clones and very prone to disease


What is an example of non-Mendelian genetics?

Blood types

*A - dominant
*B - dominant
*AB - dominant
*O - recessive


What is incomplete dominance?

Some alleles will both express, like snapdragons. Red and white snapdragons produce pink snapdragons


What is mosaicism?

Different cells in the body have different genotypes and thus express different phenotypes
—Calico cats


Females have two X’s, and one of their X’s becomes what?

Barr body - Not expressed


Some female cats have both an orange X and a black X, and their paired-yet-different-colored Barr body is not expressed. What is the result?

Calico cats with black and orange fur


A Y-linked trait is passed onto whom?

Males only


Explain X-linked dominant traits.

Father with dominant X will pass it to his daughters (X from Dad, X from Mom), but not his sons (B/c they get his Y).

Mother would give it to 1/2 to all offspring depending on if she is homozygous or heterozygous. Male and/or female.

*See slide in pictures if needed*


Explain X-linked recessive traits.

*Predominate in males*
However, homozygous females can be affected.

Carrier mother could pass ailment to a son and also make a daughter a carrier if father is unaffected.

*See slide in pictures if needed


What is extra nuclear inheritance?

Factors passed from cytoplasm
—Mito DNA from ova


What is gene conversion?

Recombination where DNA sequence from one homologous chromosome can replace a sequence on its counterpart

Example: Paternal copy of a gene can be edited in to replace the maternal copy.


What is infectious heredity?

When integrated traits introduced by a virus are passed along the line. Usually from one parent.