Genetics 4

order of dominance based on activity of alleles protein product.

Alleles can be completely dominant or recessive.

or can display forms of  incomplete dominance or co-dominance.

Network of interacting genes, produce molecule or compound as end product.

one haplo copy is enough to express wild type phenotype.

one copy is not enough to produce wild type phenotype.

decrease or complete loss of gene activity

usually recessive

alleles that have acquired a new function or are altered to express more activity than wild type allele.

complete loos of gene function

aka amorphic mutaion

partial loss of gene function aka hypomorphic mutation

multimeric proteins composed of two or more polypeptides join together to form a functional protein.  May suffer complete of partial loss

• new gene activities not found in wild type
• usually dominant

progeny has heterozygous phenotype different from each homozygous parent.

single gene mutations that cause death usually inherited as recessive   mutants, recessive alles that only kill homozygotes

sex has influences gene expression.May limitate expression on one sex but not the other.  both sexes carry the genes for sex limited traits bt genes are expressed in only one sex.

phenotype corresponding to particular genotype differs depending on sex

some dominant lethal alles sidestep natural selection by not showing abnormalities till after they have a chance to reproduce.

phenotype consistent with genotype

certain genotype fails to produce corresponding phenotype.

traits for which nonpenentrant individuals  occassionaly iccur

same genotyphe producess phenotypes that vary in the degree of expression of the allele of interest.

resulf of the influence of environmental factors (NON GENETIC FACTOR)

alteration of multilple distinct traits of an organism by mutating a single gene

collaboration of multiple genes in producing a single phenotype

network of interacting genes  produce a molecule of compound as final product

each gene produces an enzyme, each enzyme has a specific role that produces a phenotype.

test the ability of a mutant to execute each step of biosynthetic pathway , assembles steps in a pathway by  determining the point in which the pathway is blocked in each mutant.

gene interactions

an allele of one gene modifies or prevents the expression of alleles at another gene

requires genes to work in agreement to produce a single gene product

ability of two mutants with same mutant phenotype to produce progeny with wild type phenotype.  More than one gene is involved in determining phenotype.

either encode same gene product, or encode gene products  that have same effect in a single pathway or compensatory pathways.

9:6:1 ratio of phenotypes of progeny in a dihybrid cross

homozygosity for a recessive allele at one locus can mask the phenotypic expression of a second gene.

dominant allele at one locus masks the expressio of alleles at a second locus

similar to dominant epistasis, but occurs when a dominant allele of one gene completely suppresses the phenotypic expression of alleles of another gene.

mutations of different genes can produce the same, similar, or abnormal phenotypes.

mating of two organisms with same or similar abnormal phenotype can have offspring with wild type phenotype.

mutations that fail to complement one another consist of one or more mutant alleles of a single gene.

consist of mutants whose phenotypes fail to complement one another, and complement mutants in other complementation groups.