Gradebook 6/4/2018 11:55 PM A 15.6/25 de Calculator - Periodic Table Question 7
ID: 274960 • Letter: G
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Gradebook 6/4/2018 11:55 PM A 15.6/25 de Calculator - Periodic Table Question 7 of 9 Incorrect X Incorrect X FA Sapling Learning Map macmillan learning Suppose there are four newly discovered genes, each with two alleles, in humans that all follow a simple Mendelian inheritance pattern. Alleles are noted by a + or - for dominant and recessive, respectively. The genes and their phenotypes are listed in the table below. Gene Wiz Serp Time Drgn Recessive Phenotype Dominant Phenotype Have the ability to cast spells Cannot cast spells Can communicate with snakes Cannot talk to snakes Have the ability to travel through time Experience normal time Have the ability to hatch dormant dragon eggs Cannot hatch dragon eggs What is the probability of two completely heterozygous parents having a child with a Time Time Drgn Drgn genotype or a child with a Time *Time* Drgn Drgn genotype? Enter your answer as a decimal. Incorrect. Number Each of the two genotypes are mutally exclusive of one another. First, calculate the probability of two heterozygous parents having a child with the first Time .04028 and Dragn genotypes by multiplying the probabilities of obtaining the genotypes from each of the two loci. Next, calculate the probability of having a child with the second Time and Dragn genotypes using the same strategy. Finally, add these two probabilities together. Previous Try Again > Next ExitExplanation / Answer
Let us denote the genotypes using single alphabet for simplicity.
Parents are both heterozygous. Thus, their genotype will be w+w-/s+s-/t+t-/d+d-.
It involves 4 gene loci.
Required offspring genotype is t-t-/d-d- or t+t+/d-d-
Let us find individual probabilities and add them up.
(1) probability of t-t-/d-d-
On crossing the parents and considering t & d loci, we can make individual punnett square as follows:
Parents are heterozygous for every gene.
Thus let's cross t+t- and t+t- .
So probability of t-t- is 1/4.
Similarly probability of d-d- will be 1/4.
Thus, probability of t-t-/d-d-
=1/4 × 1/4
=1/16--------------------------------(i)
For t+t+/d-d-
(Same punnett square will be used)
probability of t+t+ is 1/4 and that of d-d- is 1/4.
Thus probability of t+t+/d-d-
=1/4 ×1/4
=1/16---------------------------------(ii)
Finally,
Probability of being either
Time-time-/drgn-drgn- or time+time+/drgn-drgn- will be the sum of above two.
This means,
(1/16)+(1/16)
=2/16
=1/8
=0.125 (answer).
Ans: 0.125Related Questions
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