bio unit 3+10 - genetics

gregor mendel

father of modern genetics, pea plant guy

law of segregation

allele pairs separate during gamete formation, alleles are passed down from one gen to another as distinct units

law of independent assortment

allele for one trait does not affect allele for another trait, happens in metaphase i

law of dominance

one allele is more expressed than another

mutagen

smt that causes a mutation

genotype

representation of alleles

phenotype

trait seen

pedigrees

a chart that shows a trait in a family and how it is inherited

sex linked diseases

colourblindness, hemophilia

autosomal recessive disease

disease caused by recessive alleles, albinism, cystic fibrosis, sickle cell disease

meiosis

diploid cell to haploid to make genetically different gametes

prophase I

chromosomes form, genes are exchanged on chiasma

metaphase I

homologous pairs line up randomly in middle

anaphase I

homologous chromosomes are pulled to opposite poles

telophase I

chromosomes uncoils and cell splits

prophase II

dna condenses, no replication

metaphase II

chromosomes line up in middle

anaphase II

sister chromatids pulled to opposite poles

telophase II

chromosomes uncoil and cells split into 4 haploids

oocytes

where female sex cells form, meiosis I at fetus + meiosis II at fertilization

spermatocytes

form sperm cells, every day make 4 cells per site

tetrads

4 chromatids (2 sister pairs)

meiosis I

reduction division , diploid to haploid

meiosis II

sister chromatids separate

chiasma

where crossing over happens

locus

where a gene is on a chromosome

carrier

has a recessive trait but does not show it

synapsis

pairing of homologous chromosomes

fertilization

fusion of sperm and egg

heterozygous

two diff. alleles

homozygous

two same alleles

linked trait

one of a pair of genes that tend to be inherited together

test cross

testing a genotype with an unknown type

parent generation

P generation where all the offspring get their traits from

F1 generation

offspring of the P generation

F2 generation

offspring of the F1 generation

pure breeding

two homozygous individuals-\> same offspring produced everytime

continuous variation

range of small differences in a shared trait

co-dominant allele

both alleles expressed, ex. blood

unlinked trait

genes carried on separate chromosomes

cystic fibrosis

autosomal recessive, alters mucus buildup in lungs + liver (stickier and thicker)

huntington's disease

autosomal dominant, neurodegenerative starts between 30-50yrs, loss of muscle coordination and cog. decline

sickle cell anemia

codominant genetic disease, from changed A to T in base pairs

sickle cell anemia symptoms

extreme pain, weakness, heart attack or stroke, pneumonia, bone malformations and death

pleiotropy

single gene having multiple effects

what triggers sickle cell symptoms

low oxygen levels in blood, dehydration, infection and sudden temp change

single nucleotide polymorphism (SNP)

one nucleotide being switched for another

recombinant

organism that has different combos of alleles to either of its parents, for linked genes may happen if crossing over

polygenetic traits

traits controlled by 2 of more genes

pleiotropic genes

genes that affect multiple traits

epistatic genes

genes that impact the expression of some genes

penetrance of allele

why alleles are not shown in everybody

linkage group

several genes on the same chromosome that do not show independent assortment