Question

Plants with genotypes RRTT and rrtt were mated to produce an F1 plant. The F1 plant was testcrossed to a plant with genotype rrtt. Following are the numbers and types of progeny from this testcross:

38 RrTt

42 rrtt

8 Rrtt

12 rrTt

Answer 1

Question 1) What is the genetic distance between the R and T genes?
Answer
a.
10%
b.
20%
c.
40%
d.
50%
e.
80%

Question 2) What is the genotype of the F1 individual?

Answer
a.
RRTT
b.
RrTt
c.
Rrtt
d.
rrtt

Answer 2

Hello @Lowsyharding !

\(\Huge{\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}\color{orange}{\bigstar}\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}\color{orange}{\bigstar}\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}}\\\color{white}{.}\\\Huge\sf\color{blue}{~~~~Welcome~to~OpenStudy!~\ddot\smile}\\\color{white}{.}\\\\\Huge{\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}\color{orange}{\bigstar}\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}\color{orange}{\bigstar}\color{red}{\bigstar}\color{blue}{\bigstar}\color{green}{\bigstar}\color{yellow}{\bigstar}}\)

Answer 3

Answer to question no 2 will be RrTt

Answer 4

Not sure about question 1

Answer 5

ok thanks, i'll be sure to look over it and make sure it's right. I just wanted to make sure, to get the same answer so I'm correct.

Answer 6

can u help @sarah786

Answer 7

@Somy

Answer 8

oh im sorry i don't really know this @Abhisar

Answer 9

its okay...thnx for bothering @Somy

Answer 10

@Abhisar no problem)

Answer 11

genetic differences .lemme check O.o

Answer 12

ok \(\huge\ddot\smile\)

Answer 13

Really that term new to me . 2nd one is RrTt
@shrutipande9 @Frostbite

Answer 14

@Koikkara

Answer 15

okay..it will be c

Answer 16

In genetic mapping different genes are linearly arranged according to their % of crossing over or recombination frequency or cross over frequency. Genes have different recombination frequencies depending on how closely linked they are. The genetic distance between genes is measured in map units (mu), where 1 mu is defined as the interval in which a 1% crossing over takes place. It is not a unit of physical distance like nanometers, but an indirect measure of distance on the basis of a probability. The higher this probability, the further the genes are from one another physically. The frequency of recombination is proportional to the distance between genes. The first genetic map ever constructed was based on recombination frequencies from Drosophila crosses involving the X-linked genes w (white eyes), m (miniature wings), and y (yellow body). In each cross, the number of parental progeny was much greater than the number of recombinant progeny. The percentages of recombinants were calculated for each cross. The recombination frequencies were:

w-m – 32.7 % [which means that probability of coming together of w & m genes was 32.7 %]
w-y – 1.0 % [which means that probability of coming together of w & y genes was 1.0 %]
m-y – 33.7 % [which means that probability of coming together of m & y genes was 33.7 %]

Chromosome: y__w___________________m
- 1.0 mu - - 32.7 mu –
Thus y and W are closest together since they have the lowest frequency of recombination. We also know that the m-w distance is shorter than the m-y distance, since m-y has a higher frequency of recombination than does w-m.

Answer 17

@aaronq can u pls chk this ?

Answer 18

oh wait the answer for q 1
is it 40%? @Abhisar

Answer 19

because if so it makes sense
as the next generation are
38 RrTt

42 rrtt

8 Rrtt

12 rrTt
the total number will be ur 100%
when u add up 38+42+8+12= 100 number offspring in total
that means

RrTt will be 38% meaning approximately 40%

rrtt will be 42% also around 40%

Rrtt will be 8% approximately 10%

rrTt will be 12% also around 10%


you can round off , most important thing is that in total u have to get 100% after rounding
so 40+40+10+10 will give you 100%

thus % chances that R will come with T is 40%

sorry @Abhisar i just didn't get the 'distance thing so i thought its something new

Answer 20

i still don't get 'distance' concept since i learnt this as % chances @Abhisar

Answer 21

this is according to ur info on distance concept, i hope u get it @Abhisar if not just let me know i'll explain

Answer 22

@Zale101

Answer 23

Q2 is right, good job boys @somy @Abhisar

So for Q1 RT is dominant and therfore it is a apart of the original chromosomes, meaning that it will appear together most often = when looking at map units the closer to 1% mean that they are close to the same chromosomes.

To figure this out we look at the parental which is either RT or rt, if it is a different combination we add up the columns.

since
8 Rrtt

12 rrTt

are not corresponding to rt, or RT we include them into our equation

recombinant = # of recombinant / total

20/100 = .2 x 100% = 20%

meaning that R T is 20% centimorgan apart from each other.