Question

1)A homozygous tomato plant with red fruit and yellow flowers was crossed with a homozygous tomato plant with golden fruit and white flowers. The F₁ all had red fruit and yellow flowers. The F₁ were testcrossed by crossing them to homozygous recessive individuals, and the following offspring were obtained:
Red fruit and yellow flowers41
Red fruit and white flowers7
Golden fruit and yellow flowers8
Golden fruit and white flowers44
How many map units separate these genes?

A)17.6

B)17.1

C)15

D)18.1

2)Which of the following, if damaged, would most directly hinder RNA polymerase from attaching to the beginning of a gene?

A)introns

B)exons

C)UTR's (untranslated regions)

D)snRNA

E)promoter region

Answer 1

1) Red fruit is dominant to golden fruit and yellow flowers are dominant to white flowers, let the alleles be R- red fruit, r- golden fruit

Y- yellow flower, y- white flower

plant with yellow flowers and red fruit * plant with golden fruit and white flowers

RRYY * rryy

RY/ry

F1 is test crossed, that is crossed to rryy

RrYy * rryy

	RY	Ry	rY	ry
ry	RrYy ( red fruit, yellow flowers)	Rryy ( red fruit, white flowers)	rrYy(golden fruit, yellow flowers)	rryy(golden fruit, and white flowers)

in the RrYy, R and Y alleles are on one chromosome and r and y alleles are on another chromosome, so RY and ry are parental type gametes and Ry and rY are recombinant type gametes, recombinant type progenies are formed from recombinant gametes.

here recombinant progenies are

red fruit, white flowers and golden fruit, yellow flowers

recombination frequency=( number of recombinant progenies/total number of progenies)100

= (( number of red fruit, white flowers + number of golden fruit, yellow flowers)/total number of progenies)100

= ((7+8)/100)100

= 15%

recombination frequency in percentage is the distance between genes in cM.

c) 15

2) promoters are the regions in the DNA where RNA polymerase binds if the promoter is mutated RNA polymerase cannot bind to the DNA and transcribe to RNA.

introns are found in pre-mRNA it is spliced out and exons in between are joined together, 5`UTR is the region at the 5` end of the mRNA which is not translated.

E) promoter region.