Extensions of Mendelian inheritance

Question 1

Incomplete Dominance

Answer 1

The domiant alles isnt completely express when the recessive allele is around & get a mixture of the domiant & recessive allele (ex. breeding a red flower with a white flower & getting a pink flower)

Question 2

Incomplete Penetrance

Answer 2

People with the genotype may not always express the phenotype (Lower the penetrance less likely you would express it)

Question 3

Overdominance

Answer 3

When a heterozyogte has an extreme phenotype than either of its parents

(ex. Sickle cell anemia and malaria resistance)

Question 4

Codominance

Answer 4

When both domiant alleles (genes) are expressed

(ex. ABO blood types)

Question 5

X-Linked

Answer 5

1. Inheritance of gene which is located on X-chromosome
2. Male has only one copy of the gene (hemizygous), female has two copies of the gene
   (ex. Color blindness)

Question 6

Sex Influenced

Answer 6

1. Effect of sex on the phenotype ( one allele may be dominant in male but recessive in female)
2. Sex hormone may regulate gene expression pattern

(male blindenss)

Question 7

Sex Limited

Answer 7

1. Certain trait is shown only one gender
2. Sex hormone that is produced from only one gender is essential on producing a particular phenotype
   (ex. Gender specific traits)

Question 8

Lethal Allele

Answer 8

1. An allele which is responsible for death of an organism
2. Mutated protein from lethal allele may cause detrimental effect to the organism
3. In a case of loss-of-function allele, recessive homozygote causes lethal effect to an organism

Question 9

Wild Type Allele

Answer 9

1. Produces functional protein which exerts normal/usual trait
2. There may be more than one wild-types (especially phenotypically)

Question 10

Mutant Allele

Answer 10

Other than wild-type allele that exerts different trait than normal one & May cause polymorphism (various phenotypes) & also May show altered level of protein expression or abnormal protein

Question 11

Recessive Allele

Answer 11

Character of the allele is masked by the function of dominant allele

Question 12

Dominant Allele

Answer 12

Presence of one copy of the allele is enough to exert a trait

(Produces enough protein to express phenotype)

Question 13

Gain-of-function mutation

Answer 13

Mutant gains a new or abnormal function

Question 14

Dominant-negative mutation (antimorphic mutation)

Answer 14

Encodes a protein that acts antagonistically to the normal protein & Mutated gene product may bind to normal gene product and inactivate the function

Question 15

Haploinsufficiency

Answer 15

Only one copy of the gene is functional but which is not enough to exert normal phenotype

(ex. Polydactyly)

Question 16

Gene redundancy

Answer 16

Phenomenon that one gene can compensate for the loss of function of another gene

Question 17

Causes of gene redundancy

Answer 17

Gene duplication (and subsequent mutations) & Paralogs are duplicated genes that are different due to accumulated mutations

Question 18

Epistasis

Answer 18

Gene-to-gene interaction where one gene determine if the other gene will be expressed

Question 19

In Epistatic the gene its phenotype is __________

Answer 19

Expressed

Question 20

In hypostatic the gene its phonotype is ___________

Answer 20

Supressed

Question 21

Suppressor mutation

Answer 21

Second mutation of the gene which reverses the effect of the first mutation

Question 22

Intergenic/extragenic suppressor

Answer 22

Second mutation is not on the same gene that caused phenotypic change by the first mutation

Question 23

Complementation

Answer 23

A phenomenon in which the presence of two different mutant alleles in the same organism produces the wild type phenotype .

Question 24

Holandric gene

Answer 24

A gene on the Y chromosome

Question 25

Conditional Lethal Allele

Answer 25

An allele that is lethal but only under certain environmental conditions such as a temperature sensitive mutant

Question 26

Gene Interaction

Answer 26

When two or more different genes influence the outcome of a single gene

Question 27

Gene Knockout

Answer 27

When both copies of a normal gene have been replaced by an inactive mutant gene

Question 28

Gene modifier effect

Answer 28

When the allele of one gene modifies the phenotypic effect of the allele of a different gene

Question 29

Hemizygous

Answer 29

Describes the single copy of an X-linked gene in the male. A male mammal is said to be hemizygous for X linked genes

Question 30

Intergenetic Supressor

Answer 30

A suppressor that is a different gene from the gene that contains the first mutation

Question 31

Multiple Alleles

Answer 31

When the same gene exists in two or more alleles in a population

Question 32

Nonessential Genes

Answer 32

Genes that are not absolutely required for survival, although they are likely beneficial

Question 33

Pleiotrophy

Answer 33

The multiple effects of a single gene on the phenotype of an organism

Question 34

Polymorphism

Answer 34

The prevalence of two or more phenotypic forms in a population, the phenomenon in which a gene exists in two or more alleles within a population

Question 35

Reciprocal cross

Answer 35

A pair of crosses in which the traits of two parents differ in regard to sex. Example: red eyed female crossed with a white eyed male and the reciprocal cross would be a red eyed male fly and a white eyed female fly.

Question 36

Recessive epistasis

Answer 36

A form of epistasis in which an individual must be homozygous for either recessive allele to mask a particular phenotype.

Question 37

X linked recessive

Answer 37

An allele or trait in which the gene is found on the X chromosome and the allele is recessive relative to a corresponding allele

Question 38

Semilethal alleles

Answer 38

Lethal alleles that kill some individuals but not all

Question 39

Pseudoautosomal inheritance

Answer 39

The inheritance pattern of genes that are found on both the x and Y chromosomes. even though such genes are located physically on the sex chromosomes their pattern of inheritance is identical to that of autosomal genes.

Question 40

Maternal effect

Answer 40

Genotype of the mother determines the phenotype of the offspring & the genotype of father or offspring are irrelevant to the phenotype

Question 41

Polygentic traits

Answer 41

Mnay genes coding for one trait

(ex. Our height)