non-mendelian inheritance- lecture 11

Question 1

Mendelian inheritance

Answer 1

• For every gene, there are two alleles
• Of these two alleles, one allele is dominant to the other, which is recessive

Question 2

Incomplete dominance

Answer 2

is a kind of non-Mendelian inheritance where, instead of two alleles
having a dominant and recessive relationship to each other, neither allele is dominant or
recessive. Instead of heterozygotes having the phenotype associated with one dominant allele,
they instead express an intermediate phenotype

Question 3

Codominance

Answer 3

sounds pretty similar to incomplete dominance, and the two are easily confused
for each other. But whereas traditional dominance/recessiveness involves a dominant allele masking a recessive allele, and incomplete dominance involves the amount of protein being
made, codominance is about co-expression of two different phenotypes

Question 4

Incomplete penetrance

Answer 4

Easily confused with incomplete dominance, since they both have the word “incomplete” right
there at the beginning, incomplete penetrance occurs when a phenotype associated with a
genotype does not always occur

Question 4

Variable expressivity

Answer 4

Variable expressivity is actually quite different from incomplete penetrance. With variable
expressivity, it’s not about whether or not you express the phenotype associated with your
genotype–it’s about the degree to which you express a phenotype, or the ways that you
express it.

Question 5

lethal alleles

Answer 5

will cause deviations from expected mendelian ratios

Question 6

multiple alleles

Answer 6

provide a greater number of possible genotypes/phenotypes than just 2 alleles

Question 7

multiple alleles example

Answer 7

human blood groups

Question 8

complete vs codominance vs incomplete dominance

Answer 8

In complete dominance, only one allele in the genotype is seen in the phenotype. In codominance, both alleles in the genotype are seen in the phenotype. In incomplete dominance, a mixture of the alleles in the genotype is seen in the phenotype

Question 9

complete dominance

Answer 9

Complete dominance is a condition wherein the dominant allele completely masks the effect of the recessive allele; consequently, both alleles must be recessive for the recessive allele to be expressed.

Question 10

polygenic

Answer 10

many genes contribute to the expression of one trait (skin color, height)

Question 11

pleoptropy

Answer 11

one gene has an effect on many traits (cystic fibrosis)

Question 11

epistasis

Answer 11

Epistasis is a circumstance where the expression of one gene is modified (e.g., masked, inhibited or suppressed) by the expression of one or more other genes (genes work together)

Question 12

epistasis problem

Answer 12

Question 13

sex influenced traits

Answer 13

autosomal genes can be expressed differently in males and females

Sex-influenced traits are autosomal traits that are influenced by sex. If a male has one recessive allele, he will show that trait, but it will take two recessive for the female to show that same trait. One such gene is baldness

Question 14

sex limited traits

Answer 14

Sex-limited traits are traits that are visible only within one sex. For instance, barred coloring in chickens normally is visible only in the roosters

Question 15

maternal genetic effect

Answer 15

In genetics, maternal effects occur when an organism shows the phenotype expected from the genotype of the mother, irrespective of its own genotype,

maternal genes whose products, RNA or protein, are produced or deposited in the oocyte or are present in the fertilized zygote

Question 16

name some characteristics of cytoplasmic inherited traits

Answer 16

not all genes are encoded in the nuclear chromosomes

Question 17

genetic imprinting

Answer 17

an allele is differentially expressed, depending on whether it is inherited from the male or female parent

Question 18

sex linked traits

Answer 18

Sex-linked, as related to genetics, refers to characteristics (or traits) that are influenced by genes carried on the sex chromosomes. In humans, the term often refers to traits or disorders influenced by genes on the X chromosome, as it contains many more genes than the smaller Y chromosome.

Question 19

maternal effect gene

Answer 19

mother supplies mrna or protein to the egg that is essential for development

Question 20

genetic maternal effect

Answer 20

direction of turning of shell
genotype says shell should turn toward the left because that is dominant but because the mother is ss and recessive, they turn to right because genotype of mother determines phenotype of offspring

Question 21

mitochondrial diseases

Answer 21

lhon

Question 22

mitochondrial replacement therapy

Answer 22

Question 23

environmental effects: temperature sensitive allele

Answer 23

allele whose product is functional only at certain temperatures

Question 24

environmental effects: maternal environment

Answer 24

environment of mother can influence offspring genotype