Bio 30 BRHS
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- If the parent's of a certain group of offspring are Rr & rr, what is the ratio of dominant compared to recessive?
- 1:1
-
If an unknown genotype is test crossed with a recessive genotype and the outcome shows that only the dominant gene is present, the unknown must be:
a) homozygous dominant
b) heterozygous dominant - a.
-
Red flowers are crossed with white flowers. The offspring shows a new pink color. This kind of incomplete dominance is:
a) codominance
b) intermediate inheritance -
b.
intermediate inheritance is when a new phenotype is present. Codominance is when both phenotypes are present at the same time(ex. roan calf) - If an individual crossed a pea that was green and wrinked with another pea that was yellow and round, would the shape genes affect the colour genes?
-
no.
Independent Assortment.
The genes that govern pea shape are inherited independently of the ones that contol pea color. - What is epistasis?
-
Epistasis is when gene(s) mask the expression of other genes.
ex. chicken combs - Incomplete dominance ONLY happens when...
- neither gene exerts a dominant influence.
- What is the difference between monohybrid crosses and dihybrid crosses?
- Monohybrid crosses only deal with one trait(pea shape - Ss), while dihybrid crosses deal with two traits at the same time(pea shape & pea color(Cc) - SsCc)
- How do u find a cross over percentage?
-
divide the number of recombinations by total number of offspring and then multiply by 100.
- that percent would equal the same amount of distance on a chromosome map(7% = 7 units) - Can males be heterozygous for sex linked trait?
-
no.
males cannot carry a trait on their Y chromosome, therefore they will only have one trait and that will be on the X, which is given by the mother. - A pair of genes seperate during the formation of sex cells. This process is called?
-
Segregation
- happens during meiosis -
Which is the genotype:
a) black
b) TT -
TT
- a genotype is the DNA code that refers to the genes an organism contains - One gene masks the effect of another. This process is known as the principle of?
-
Dominance.
ex. black(T) is dominant over brown coat color(t), therefore the black will mask the brown. -
Parents: MmSs x mmss
What will the gametes be? - [MS],[Ms],[mS],[ms] x [ms]
- DdFf x DdFf are crossed. What will the ratio of the f2 be?
-
9:3:3:1
9 - dominant for both(D_F_), 3 dominant for D only(D_ff), 3 dominant for F only(ddF_), & 1 both recessive(ddff)