genetics definitions exam 2

haplosufficient

having one copy is enough for the normal function in heterozygous

haploinsufficient

one copy is NOT enough for the normal function

loss of function

there is a significant decrease overall loss of function gene product

gain of function

the gene product gains an increas or even a whole new function for wild type activity

null mutations/ amorphic mutations

loss of function mutations producing no sense of functional gene product, most of the time lethal when its homozygous

leaky/hypomorphic mutation

loss of function mutations resulting partial loss depend on level of activity of the leaky mutation

dominant negative mutation

multimeric proteins composed of two or more polypeptides joining together forming a functional protein, dominant due to loss of function of the multimeric proteins "spoiler effect"

spoiler effect

mutant alleel interacts with normal protein and disrupts full protein

hypermorphic

mutations produce more gene activity than usual (gain of function, dominant)

neomorphic

mutation give genes a brand new function not found in wild types (dominant)

incomplete/partial dominant

occurs when neither allele hides the other forming a blend

codominance

leads to heterozygotes with different phenotypes BOTH alleles being shown at the same time more than one pattern of dominance may exist btwn diff alleles

allelic series

an order of dominace among the alleles forming sequential series

lethal alleles

some single gene mutations that are detrimental that can cause death, resseively inherited, homozygotes die , rare

complete pentertance

given genotype is always producing the same phenotype

sex linked/limited traits

both sexes carry the genes for such traits but only expressed in one sex due to the hormones

sex influenced traits

phenotype corresponding to certain genotype differs depend on gender

penetrant

phenotype is consitent with the genotype organsim has genotype and shows it

nonpenetrant

organism does not produce the phenotype (has gene does not show)

fully penetrant

genotype always expressed in the phenotype

incomplete penetrant

nonpenetrant (non producing) shown in some individuals

variable expressity

individuals who carry the allelel for a trait but with different features

pleiotropy

alteration of multiple distinct traits by a mutation of single gene affecting multiple different traits

gene interaction

collaboration of multiple genes working together to produce a trait/ phenotypic characteristics

genetic dissection

experimental approach taken to investigate genetic pathways

epistasis

two or more genes interact to produce one phenotype

complementary gene

recognize 2 genes to produce overall color, genes work in tandem to produce a single product (9:7)

duplicate gene action

encode same product encode products have same effect in pathway (15:1)

dominant gene interaction

(9:6:1)

recessive epistasis

homozygosity for a recessive allele of one gene hides the effect of a second gene (9:3:4)

dominant epistasis

dominant allele at one locus will mask the phenotypic expression (12:3:1)

dominant supression

dominant allelel at one locus completely expresses of alleles at second locus (13:3)

variable expressity

when individualsare carrying the allele but expressed with different features

S phase

the stage of the cell cycle where the DNA replication occurs and chromosomes duplicated

chromsome

a dna protein structure containing genes and carrying all the genetic material in a cell

synapsis

the paring of homologous chromosomes during prophase I in meiosis

SRY gene

the specific gene on "Y" which initiates the male sex determination

Z/W sex determination system

a system where the females are "ZW" and males "ZZ" =, females determine sex offspring

chiasmata

the "X" shaped cross over which chromosomes exchange their DNA

centromere

the region of a chromosome that is holding the sister chromatids together to attach to the spindle fibers

sister chromatids

two identical copies of a replicated chromosome joined at a centromere while separated

centrosome

the cellular structure that organizes microtubules forming spindle during cell division .