chapter 3 Flashcards
autosomes
chromosomes other than sex chromosomes, 1-22
sex chromosomes
chomosomes of sex deterimination
dimorphic chromosomes
shape, gene content, and expression is different from autosomes
sex chroosomes act as ______ during meiosis
homologous chromosomes
recessive sex-linked mutations affect ______
heterogametic sex
different sexes have different __________ on sex linked loci
numbers of alleles
tops and bottoms of both X and Y chromosomes
pseudoautosomal region
pseudoautosomal regions
promote chromosome pairing and help control the final gametes
SRY gene
transcription factor that turns on development pathway for men
hemizygous
inheriting 1 chromosome for sex determination
heterogametic
males have 1 X and 1 Y, phenotype of single allele is immediatley observed
autosomal dominance
- can’t pass without it
- equal in males and females, passed on by both
- doesn’t skip generations
autosomal recessive
- usually rare
- equal in males and females, tends to skip gens
- affected usually born to unaffected parents
- can be caused by inbreeding
X linked recessive
- More males affected, daughters of affected males are carriers
- 1/2 sons of affected females are affected
X linked dominance
- both males and females affected, doesn’t skip gens
- Affected father passes to all daughters
- affected son must have affected mother
product rule of probability
multiply the prob of independent events happening at the same time
sum rule of probability
add probability of 1 out of 2+ mutually exclusive events (either/or)
mendel’s second rule
gene pairs on different chromosomes assort independently during gamete formation
linked genes
alleles on the same chromosome
unlinked genes (;)
alleles on different chromosomes
monohybrids
heterozygous for different alleles for 1 gene (A/a)
dihybrids
heterozygous for different alleles on two genes (AB/ab)
unlinked dihybrids
A/a; B/b, segregate independently
linked dihybrids
AB/ab or Ab/aB, segregate independently or ignore recombo
unknown linkage
A/a * B/b
independent assortment frequency calculation
determined with product rule of F2 phenotypes
genetic analysis
outcomes of genetic crosses can have random fluctuations by chance as offspring inc
larger sample size _____ chances of deviation
decreases
purpose of chi squared analysis
check probability that data will diverge this far from theoretical ratio if null hypothesis is correct
what p val is accepted to reject the null hypothesis
p < 0.05
what is needed for chi squared analysis
sample size, degrees of freedom, random fluctuation
chi squared equation
x^2 = sum ( ( observed - expected) ^ 2 / expected ), returns p value
2 steps of chi squared
1) form hypotheses (null and expected)
2) determine how close actual is to expected (goodness of fit)
degrees of freedom
calculate with n - 1 (n is num of categories)
