BIOL 3000 Final AUBURN

pangenesis

particles carry genetic information from different parts of the body to the reproductive organs; "in my hand are tiny versions of my hand"

epigenesis

somatic cells vs. gametes; only the information in the egg/sperm is passed on to the next generation

preformationism

genetic information is passed down from mother OR father only

germ-plasm theory

cells in the reproductive organs carry a complete set of genetic information

transmission genetics

encompasses basic principles of heredity and how traits are passed down from one generation to the next

molecular genetics

chemical nature of the gene itself; how genetic information is encoded, replicated, and expressed

population genetics

genetic makeup and dynamics over space and time (i.e. evolution) of entire populations

cytogenetics

chromosomal biology, including structure, function, variability, and disease

genomics

content, organization, structure, and function of entire genomes

interphase

extended period of growth and development between cell division

G1

cell grows and proteins are synthesized

S phase

where DNA is replicated

G2

more cell growth and additional biochemical events

M phase

cell undergoes division; cell's chromosomes separate and divide (mitosis)

haploid number

single set of chromosomes (reproductive cells)

diploid number

two sets of genetic information (body cells)

prophase

chromosomes condense and become visable; each chromosome has 2 chromatids; spindle forms

prometaphase

nuclear membrane disintegrates; spindle enters nuclear region; microtubule from one of the centrosomes anchors to the kinetochore of the sister chromatids

metaphase

chromosomes are aligned in the middle

anaphase

connection between sister chromatids breaks down and sister chromatids move toward opposite spindle poles

telophase and cytokinesis

chromosomes arrive at spindle poles, nuclear membrane reforms and cytoplasm divides

prophase I

chromosomes form homologous pairs; crossing over takes place; chromosomes condense; nuclear membrane breaks down and spindle forms

metaphase I

homologous pairs of chromosomes align along metaphase plate

anaphase I

separation of homologous chromosomes

telophase I

chromosomes arrive at spindle poles and cytoplasm divides

prophase II

chromosomes recondense; spindle reforms; nuclear envelope breaks down

metaphase II

individual chromosomes line up on the metaphase plate

anaphase II

kinetochores of sister chromatids separate, and chromatids are pulled to opposite poles

telophase II

chromosomes arrive at poles; nuclear envelope reforms; cytoplasm divides

crossing over

homologous chromosomes exchange genetic information

chiasmata

points where crossing over is occurring

recombination

creating new combinations of alleles on a chromatid

genotype

set of alleles that an organism possesses

phenotype

manifestation or appearance of a characteristic

heterozygote

two different alleles

homozygote

two identical alleles

alleles

different versions of a gene

gene

inherited factor that determines a characteristic

locus

specific place on a chromosome where particular gene and alleles are found

Mendel's "recipe for success"

-made sure he could clearly identify different 'forms' among the progeny.

-counted each generation separately to correctly deduce ratios and allow for backcross.

-did large number of crosses and also reciprocal crosses.

-used summary statistics to compare observed vs. expected ratios.

the principle of segregation (Mendel's 1st law)

During gametogenesis, pairs of alleles separate (segregate). Each gamete receives one or the other randomly. There is an equal chance that the copy from the individual's mother or father is present in a gamete. -- happens in anaphase I

the principle of independent assortment (Mendel's 2nd law)

alleles at separate loci segregate independently from one another -- alleles at different loci combine randomly in gametes -- metaphase 1?

assuming no recombination has occurred, what stage of meiosis explains the principle of segregation?

anaphase I

assuming no recombination has occurred, what stage of meiosis explains the law of independent assortment?

metaphase I

Mendel's big six

-AA x AA = all AA

-aa x aa = all aa

-AA x aa = all Aa

-Aa x Aa = 1AA : 2Aa : 1aa

-Aa x aa = 1Aa : 1aa

-AA x Aa = 1AA : 1Aa

dihybrid F1 phenotype (Aa x Aa)

3:1

double homozygote phenotype

all same

dihybrid dominant backcross phenotype (Aa x AA)

all show dominant trait

dihybrid recessive backcross phenotype (Aa X aa)

1:1

addition rule

the probability of two or more mutually exclusive events is calculated by adding the probability of these events

*add within a cross

multiplication rule

the probability of two or more independent events is equal to the product of their individual probabilities

*multiply between crosses

backcross

cross between an F1 individual and one of the parental; used for determining dominance

testcross

cross between an individual with an unknown genotype and an individual with a homozygous recessive gene; used for determining an unknown genotype

reciprocal crosses

pair of crosses which the phenotypes of the male and female parents are reversed

chi-squared & degree of freedom equations

- X^2 = ∑(observed-expected)2/expected

-df = n-1

complete dominance

one trait is completely dominant over the other and normal mendelian ratios are observed

incomplete dominance

heterozygote is a mix of both traits (1:2:1 ratio)

co-dominance

heterozygote expresses both traits fully and simultaneously (1:2:1 ratio)

pleiotropy

multiple phenotypic effects resulting from a single gene

penetrance

the proportion of genotypes that actually express the diseased phenotype

expressivity

individuals with the same genotype show different degrees of the same phenotype

dominant lethal vs. recessive lethal

dominant lethal can only last one generation; recessive lethals can be carried and you must have two recessive alleles

semi-lethal

an allele whose expression makes death more probable

semi-sterile

an allele whose expression makes reproduction less probable

conditional lethal

lethal alleles whose expression is dependent on environmental conditions

delayed expression

the expression of a trait is not expressed until later in life; how dominant lethals can be passed on

recessive lethal heterozygous cross

2:1 (1/4 will die)

dominant lethal heterozygous cross

1 (only the homozygous recessive will live)

haplodiploidy

ploidy determines sex (i.e. bees)

dosage compensation

small X in females makes up for difference in males (X inactivation)

sex linkage

mode of inheritance resulting from loci being located on the same sex chromosome

what kind of cross would you do to test for sex linkage?

reciprocal cross

sex limited inheritance

a trait that is expressed in only one sex even though both sexes carry the alleles; found on autosome; males and females will have the same genotype, but different phenotypes

sex influenced inheritance

traits are expressed differently in males and females; found on autosome; trait has a higher percentage in one sex

epistasis

interaction between two or more loci that affect a single trait

-when an allele at one locus masks the effects of alleles at one or more loci

-when two or more loci interact to create new phenotypes

-when an allele modifies

linkage group

gene located together on the same chromosome; travel together in meiosis, are not expected to assort independently

coupling (cis) configuration

repulsion (trans) configuration

why does calculating the proportion of recombinant gametes yield information about distance?

the frequency of recombination can give us an idea about how far away they are from each other; what are the odds at this distance, they will cross over

how to calculate MU

(# of recombinants/total progeny) x 100

how do you identify your NCOs?

2 most common phenotype

how do you identify your DCOs?

2 least common phenotype

what information to you need to determine order?

compare the NCO to DCO and see which one changed, that is what is in the middle

what information do you need to determine distance

single crossover ratio + double crossover ratio

what are you going to add together, divide by, etc

to determine ratios, add the NCO/DCO/single crossovers that match and divide by the total progeny

karyotype

complete set of chromosomes possessed by an organism

karyogram

chromosome stained and arranged for viewing -- analyze a karyogram to see if it's a karyotype

ideogram

a schematic depiction of the characters size, centromere position, and banding proteins

cytogenic location

chromosome #, p or q, region, band, subunit

euploidy

different multiples of entire sets of chromosomes

aneuploidy

an abnormal number of chromosomes, usually a gain or loss of one chromosome

monoploid (x)

number of chromosomes in a unique set

autopolyploid

duplication of the same genome; 1 ancestor

allopolyploid

duplication resulting from uniting of two different gametes at the species level or higher; more than one ancestor

cause of abnormal euploidy

-errors in fertilization

-unreduced gametes (due to nondisjunction)

-hybridization between species)

sex chromosome aneuploids

phenotypes generally result from wrong dosage of genes which escape X-inactivation

why is sex aneuploid more common?

-X chromosome inactivation

-few genes on Y

turner's syndrome

XO; monosomy X; 2n-1=45

klienfelter's syndrome

XXY; trisomy; 2n+1=47

trisomy X

XXX; 2n+1=47