Genetics

Front 1

When is incomplete dominance exhibited?

Back 1

When the heterozygote has a phenotype intermediate between the phenotypes of the two homozygotes

Front 2

What is the phenotype ratio during a heterozygotes cross that has incomplete dominance?

Back 2

1:2:1

Front 3

What is complete dominance?

Back 3

Phenotype of hte heterozygote is the same as the phenotype of one of the homozygotes

Front 4

What is codominance?

Back 4

Phenotype of the heterozygote includes the phenotype of both homozygotes

Front 5

What is incomplete penetrance?

Back 5

refers to a genotype that does not always express the expected phenotype. Some individuals possess the genotype for a trait but do not express the phenotype.

Front 6

What is the formula for the amount of genotypes possible with different alleles?

Back 6

[n(n+1)]/2

Front 7

What is gene interaction?

Back 7

When genes at different loci combine to form different phenotypes that are not predictable from a single loci.

Front 8

What is epistasis?

Back 8

During the effect of gene interaction, there is one gene that masks the effect of another gene at a different locus.

Front 9

What is an epistatic gene?

Back 9

the gene that does the masking in epistasis

Front 10

what is the hypostatic gene?

Back 10

the gene whose effect is masked

Front 11

What is recessive epistasis?

Back 11

This is when a homozygous recessive genotype at one locus affects the phenotypic outcome of an allele at a different locus.

Front 12

What is dominant epistasis?

Back 12

only a single copy of an allele is needed to inhibit the expression of the allele at a different locus

Front 13

What is a complementation test used for?

Back 13

used to determine whether two mutations occur at the same locus (are allelic) or occur at different loci

Front 14

How do sex-influenced and sex-limited traits differ from sex-linked traits?

Back 14

both sex-influenced and sex-limited traits are encoded by autosomal genes whose xpression is affected by the sex of the individual organism possessing the gene. Sex-linked traits are encoded by genes on the sex chromosomes.

Front 15

What is the genetic maternal effect?

Back 15

the phenotype of the offspring is determined by the genotype of the mother

Front 16

What is cytoplasmic inheritance?

Back 16

the genes for a character are inherited from only one parent

Front 17

How might you determine whether a particular trait is due to cytoplasmic inheritance or to genetic maternal effect?

Back 17

a trait due to cytoplasmic inheritance will always be passed through females. Traits due to maternal effect are encoded by autosomal genes and can be passed by males, although the resulting genotype of offspring reflects only the maternal parent's genotype.

Front 18

What is genomic imprinting?

Back 18

the differential expression of genetic material depending on whether it is inherited from the male or female parent

Front 19

What is a sex-influenced characteristic?

Back 19

genes on autosomal chromosomes that are more readily expressed in one sex

Front 20

What is a sex-linked characteristic?

Back 20

autosomal genes whose expression is limited to one sex

Front 21

what are polygenetic characteristics?

Back 21

characteristics encoded by genes at many loci

Front 22

What is pleiotropy?

Back 22

one gene affects multiple characteristics

Front 23

What is a pedigree?

Back 23

a pictorial representation of a family history

Front 24

What is consanguinity?

Back 24

mating between closely related people

Front 25

What is genetic counseling?

Back 25

a field that provides information to patients and others who are concerned about hereditary conditions

Front 26

What is typical of autosomal recessive traits?

Back 26

Apper equally in both sexes and seem to skip generations

Front 27

What is typical of autosomal dominant traits?

Back 27

Appear equally in both sexes and do not skip generations

Front 28

What is typical of x-linked recessive traits?

Back 28

Appear more frequently in males but are not passed from father to son

Front 29

What is typical of x-linked dominant traits?

Back 29

-affect both males and females
-do not skip generations
-fathers pass traits on to all daughters and females are more likely to be affected
-hetrozygous mothers pass the trait on to half of the progeny

Front 30

What is typical of y-linked traits?

Back 30

-appear only in males
-passed from father to all his sons

Front 31

What is preimplantation genetic diagnosis?

Back 31

-when genetic testing is combined with invitro fertilization to allow the implantation of embryos that are free of a specific genetic defect
- allows people with a genetic defect to avoid producing a child with the disorder

Front 32

What does monozygotic mean?

Back 32

twins result from a single egg (identical)

Front 33

What does dizygotic mean?

Back 33

twins arise when two seperate eggs are fertilized by two different sperm

Front 34

What are linked genes?

Back 34

genes located closely together on the same chromosome and belong to the same linkage group

Front 35

What are nonrecombinant gametes (parental gametes)?

Back 35

gametes that contain only original combinations of alleles present in the parents

Front 36

What are recombinant gametes?

Back 36

gametes with a new combinations of alleles

Front 37

What is coupling or cis configuration?

Back 37

wild-type alleles are found on one chromosome and mutant alleles are found on the other chromosome

Front 38

What is repulsion or trans configuration?

Back 38

each chromosome contains one wild-type and one mutant allele

Front 39

What is interchromosomal recombination?

Back 39

among genes on different chromosomes

Front 40

What is intrachromosomal recombination?

Back 40

due to crossing over betwen loci on the same chromosome

Front 41

What are genetic maps?

Back 41

chromosome maps calculated by usings the genetic phenomenon of recombination

Front 42

What are physical maps?

Back 42

chromosome maps calculated by using physical distances along the chromosome

Front 43

What is a two-point testcross?

Back 43

a testcross between two genes

Front 44

What is deletion mapping?

Back 44

a homozygous individual for a recessive mutation (gene of interest) is crossed with an individual that is heterozygous for a deletion

Front 45

What is somatic cell hybridization?

Back 45

requires fusion of different types of cells -- mouse and human cells are fused and based on what survives crossing gives evidence towards what genes are where