Genetics and evolution | Quizlet

Agents of evolution

mutation,gene flow,nonrandom mating,genetic drift,selection

early idea:mixing inheritance

mating white and black horse after a while makes zebra

Evolution happens when

There is a genetic variation and individuals with certain (genetic)traits survive and reproduce at higher rates than others

Particulatr inheritance

Genes are inherited in units=genes

Gradualism vs. Catastrophism

Change goes slowly vs in jumps

Name stages of mitosis and meiosis in respective order

Mitosis:interphase,prophase,metaphase,anaphase,cytokinesis. Meiosis:interphase 1,prophase1,metaphase 1,anapahse1,anaphase1,prophase2,metaphase2,anaphase2

What happens during interphase?

cell copies DNA in preperation for mitosis or meiosis

What happens during prophase?

chromatin denses into chromosomes,nuclear membrane breaks down,microtubules invade nuclear space and attach to centromeres

What happens during metaphase?

chromosomes line up along(imaginary) metaphase plate

What happens during anaphase?

chromosomes break at centromeres and sister chromatids move to the opposite side of the cell

What happens during telophase and cytokinesis?

Cell divides,nuclear membrane reforms,chromosomes unwind into chromatin

which is random and which is not?mutation and natural selection?

mutation - random,nat selection-no

example of modern evolution

antibiotic resistance

evolution misconception

does not look into the future,no purpose,no goal,no direction,no moral or immoral,theory thus teseble,we can observe now

Requirments for evolution

Vriation in reproductive sucsess

genetic basis of variation

positive correlation in trait and reproductive sucsess

Homology

a trait in two or more species inherited from a common ancestor

examples of morphological homology

hand,paw

types of homology

morphological

developmental

molecular

What is molecular homology

all species share the same genetic code

vestigial organs

organs which lost their functions and are not used anymore(example whale)

convergent evolution

evolution can take the smae direction independently

give an example of convergent evolution

sugar glider and flying squirel wjich did not have a common ancestor

endemic species

species which are found only in one place in the world in isolated areas(australia,himalai

What is Genetics?

study of heredity and hereditary variation

True breeding

allways produce same organism during self polination

Hybridization

crossing 2 true breeding variaties

Mendels first law

heterozygotes produse equal number of gametes with one of two alleles

second law or law of independe assortment

alleles of different genes split independently producing 9:3:3:1 ratios in F2 generation during dihybrid cross

Test cross

the breeding of an organism with a homozygous recessive in order to determine whether an organism is homozygous dominant or heterozygous dominant for a given trait

Heterozygote

organism that inherits two different alleles for a given gene

monozygote

yy or YY

monohybrid cross

cross between two homozygous organisms

Dihybrid cross

two true breeding with two different characteristics.In F2 give9:3:3:1 according to the law of independent assortment

locus

position of a gene on a chromosome

which probability rules are used in genetics?

Addiction rule,product rule,conditional chance

for which purpose cell division happens

reproduction

growth

repair

distinguish sexual and asexual reproduction

sexual=two parents give genes which are inherited by new organism

asexual=a single parent passes its genetic information

chiasmata

exchange between homologous non-sister chromatids resulating in crossover(happens during prophase1)

differences between spermogenesis and oogenesis

all sperm cell are functional while only one of 4 ovum is functional

Factors that contribute to genetic variation

independent assortment

crossing over

random fertilisation

How mitosis and meiosis are different?

during meiosis all stages excep interphase are repeated after Telophase 1.The result of mitosis are 2 dauter diploid cells,and of meiosis 4 haploid cells

kinetochore

A specialized region on the centromere that links each sister chromatid to the mitotic spindle.

particular inheritance

characteristics are inherited as disttrict entities(genes)

wildtype

nonmutant phenotype-not always dominant

why Mendel was lucky?

good choise of organisms:diploid,cross/self fertilisation

genes in peas are complletly dominant

one gene determines the trait,not very environmentally dependant expressio of genes

complete dominance,incomplete dominance and codominance

only dom.allele expresses its trait

some third result is made(for ex white and red give pink)

both traits are expressed(both colurs are present)

Rrlarions between ABO blood grouls

A and B are codominant with eanch other and both are dominat over O

blood transfusion

...

Penetrance

The percentage of individuals with a particular genotype that actually displays the phenotype associated with the genotype.

Expressivity

the degree to which a genotype is expressed in an individual

Pleutrope

one gene affects expression of multiple phemotypes

Epistasis

a gene at one locus alters the phenotypic expression of a gene at a second locus

dublicate gene action

when dominant allele of both gene loci produce the same phenotype without cumulative effect(15:1 ratio)

Complementation

Two different mutations in the heterozygous condition are exhibited as the wild-type phenotype; indicates that the mutations are at different loci. (9:7)

regulatory gene

a gene that sffects other gene(supressor for ex)

recessive epistasis

9:3:4 ratio

Autosomes

Any chromosome that is not a sex chromosome

environmental sex determination

sex is determined fully or in part by environmental factors

sex limited traits

(not X chromosome linked)trait is expressed only in one sex(milk production in mamals) probably because of transcription factors

sex dependent trait

trait is expressed differently in both sexes(boldness in humans)

Barr body

Inactivated X chromosome in females

Lyon hypothesis

X inactivation is random in each cell but the same in all dauter cells

Epigenetic inheritance

heritable change in gene expression(don't confuse Lamark

genomic imprinting

a phenomenon in which expression of an allele in offspring depends on whether the allele is inherited from the male or female parent

uniparental inheritance

progeny inherit organelle genes exclusively from one parent but not the other(mitochondria are inherited only from mother)

how to calculate recombination frequency?

(n of recombinants/total offspring)×100%

when more and when less recombination occurs?

more when the distance between two loci is bigger

between which numbers recombination freq varies?

0-0.5

recombination is a result of

crossing over

linkage map can be build from

recombination frequency

Morgan Units

units of measure used to position linked-genes on a chromosome in relation to one another(in %)

Non-disjunction

Error in meiosis in which homologous chromosomes fail to separate.

Euploid

an individual with the appropriate number of chromosomes for their species

Polyploid

having three or more of each type of chromosome characteristic of the species

Aneuploidy

Abnormal number of chromosomes.

Monosomy

missing a chromosome(2n-1)

Trisomy

a condition in which an extra copy of a chromosome is present in the cell nuclei, causing developmental abnormalities.(ex Dauni syndrome)(2n+1)

Non disjunction of sex chromosomes

XO or XXY or XXX

Deletion

chromosomal segment is absent

Dublication

chromosomal segment is doubled

Inversion

Chromosomal segment is reversed

Translocation

chromosomal segment is moved to other location

polygenetic trait(quantitive genetics)

two or more genes have an addictice effect on a single phenotypic character(most of ohenotypes are defined by many genes)

population genetics

the study of how populations change genetically over time

Microevolution

changes within populations or species

macroevolution

Evolutionary change above the species level.

sourses of genetic variation

ramndom mutations and recombinations

sourses of populatoon evolution

change in allele frequencies caused by

genetic drift,

gene flow

natural selection

what is bigger genetic vatiation or phenotypic variation and why

phenotypic varation is larger since it icludes genetic variation and environment

phenotypic variation in time

season

age

social environment

development

allozygotes

an individual homozygous at a given locus, whose two homologous genes are of independent origin, as far as can be

why are humans are more complex than mice and worms depite having same genes

because of regulatory DNA

mutation

heritable change in nucleotide sequence of DNA

Hardy-Weinberg equilibrium

the state of population in which frequencies of alleles and genotypes remain constant grom generation to generation,provided that only Mendelian segregation and recombination of alleles arr at work

give an equation for HW eauilibrium

frequency of genotypes: p ² + 2qp +q ² =1

where p=A1

q=A2 genotypes

define population

group of individuals that exchange genes

Define gene pool

the set (sum)of all genes, or genetic information, in any population

how to find number of possible genotypes?

see formula in the notebook

state conditions for Hardy-Weinberg equilibrium

no mutations

random mating

there are no subpopulations that differ in allele frequency

no natural selection:all genotypes have equal variability and fertility

very large population size:allele frequensies do not change by chace

no gene flow=no migration

genetic drift

random change in allele frequencies that occurs often in small populations