BIOL 101 Chapter 12: Patterns of Inherited Traits

character

a heritabke feature that varies among individuals such as flower color

trait

each varient for a character

why did he use peas

short generation times

large offsrping numbers

mating could be controlled

true breeding

plants that produce offsprng of the same variety when they self pollinate

hybridizaion

mating two contrasting true breeding varieties

Law of segregation

the processs that when alleles are inherted, only one allele in inherted and traits are nto blended together. for example a purple and white flower do not produce a light purple flower but a purple OR white flower.

what did mendel call genes

heritable factors

mendel’s model

explais the 3:1 inheriranc pattern observed in offspring

1. altenrativ e verisions of genes account for variations in inherited characters

2. each chacter an organism inherits two alleles one from each parent

3. the dominent allele determines the organism’s appearance

4. law of segreagtaion, the two alleles for a hertitable trait seggregate during gamete formation and end up in different gametes

alleles

alternative versions of gene

punnet suqares

shows possible combonations of sperm and eggs

are heterozygotes true breeding?

no becuse an orgnaisms traits does not reveal its genetic composition.

it coukd carry the gene but its recessive so it doesnt show but is presen

phenotype

ohysical appearence

genotype

genetic makeup

testcross

to determine if a phenotype is dominant or heterozygous the testcross and breed the inidividual with a homozygous recessive individual and if any offspring display the recessive phentoype \then the individual must be heterozygous

law of independent assortment

alleles for different genes separate (assort) independently during gamete formation (meiosis)

applies to genes on different non homologous chromosomes or those far apart on the same chromosme

genes located near each other on the same chromosome tend to be inherited together

monohybrids

they were heterozygous for one character

monohybrid cross

a corss between heterozygotes

dihybrid cross

determines whetehr two characteristics are transmitted to offspring togetehr or independent,y

complete dominance

when phenotypes of the heterozygote and dominant homozygote are identical

incomplete dominance

the phenotype of F1 hybrids is somewhere bwteen of the two parental varieties

codominance

two dominant alleles affect the phenotype in seperate ways

multiple alleles

most genes exist in populations in more than 2 allelic froms.

the human blood type is determined by three allels

quantitiative chaacters

vary in the population along a continum

height, skin color, shoe size

result of polygenic inheritance

multifactoral

traits that depend on multiple genes combined with enviornmental influences

pedigree analysis

used to make predictions about future offspring

carriers

recessively inherited disorders show up in inidviduals homozygou for the allel

cerriers are hetero who show no phenotype but caryy it

2 carriers have a chance of offspring haveing homozyg recessive

cystic fibrosis

result in defective or absent chloride transport channels in plasma membranes

sickle cell disease

caused by a single substitution of a amino acid in the hemoglobin protein in red blood cells

some heteros are healthy but may sufeer some symptoms

dominantly inherited disorders

arise by mutation

achondrioplasia is a from of dwarfism caused by a rare dominant allele

huntington disease

degenerative deisease of nervous system

amniocentesis

the amniotic fluid is removed and tested for disorders

chorionic villus sampling

a sample of the placenta is removed and testedn

newborn screening

phenylketonuria

cases and an amino acid it build up in the body