Im not exactly sure how to set up this problem, I would really like to know how
ID: 208855 • Letter: I
Question
Im not exactly sure how to set up this problem, I would really like to know how to do this part of the sheet, it involves #37-40.
estions 37-40 refer to the following. In a plant, T is dominant to terminal flower (t) and red fruit colorIs axial flower ed by two dominant to yellow (y These effects are caus independently assorting autosomal genes. 37. When an individual axial, red plant was crossed-with a TT Y terminal, yellow plant, the Offspring ee 4 axial-ed: 1/4 axial, yellow: 1/4, terminal, red: 1/4 terminal, yellow. The genotype of the axial,red plan a) TTYx b) Ttrx c) TTYy 38. In a second cross, an individual terminal, red plant was crossed with an individual axial, yellow plant to produce genotype of the crossed terminal, red plant was: a) ttyy b) ttry the 39. In the cross described in question 38, the genotype of axial, yellowparent was:TTyy G · 40. In a thiid cross, an individual terininal, red plant was CEossed axtakered: 3/8 terminal. Eed: 1/8-axial, yellow. 1/8 with an individual axial, red plant to produce offspring which were 3/8 terminal, yellow. The genotype of the crossed axiai, rea plant was:Explanation / Answer
37. Since the some offsprings phenotypes included terminal and yellow, the axial red parent has to be heterozygous that is TtYy
then only a cross between terminal yellow parent ( who will be homozygous recessive for both the gene- ttyy) will give offsprings of those phenotypes in that ratio
Parents- TtYy(axial red) x ttyy (terminal yellow)
Gamets- TY Ty tY ty X ty ty ty ty
Offsprings TtYy(axial red): Ttyy(axial yellow): ttYy(terminal red): ttyy(terminal yellow)= 1:1:1:1
So the answer is TtYy
38 and 39. The terminal red parent plant will be homozygous for flower position gene that is tt (since it is recessive it has to be homozygous to express). Since the two types of offsprings had only red flowers then the flower colour gene in this parent has to be homozygous too, that is YY.So the answer is ttYY
The axial yellow parent has to be heterozygous for flower postion since it can give offsprings with terminal and axial flowers. Since it has a recessive phenotype of flower colour(yellow) expressing then it will be homozygous for that gene. then its genotype is Ttyy
the only a cross between ttYY X Ttyy can give
TtYy (axial red)and ttYy(terminal red) in 1:1 (1/2:1/2) ratio
40. The genotype of the axial red parent is TtYy since the offsprings included both axial and terminal as well as red and yellow phenotypes
parents ttYy X TtYy
gametes tY and ty TY Ty tY ty
Crossing them we will get TtYY(axial red), TtYy(axial red),TtYy(axial red), ttYY(terminal red), ttYy(terminal red),ttYy(terminal red),ttyy(terminal yellow) and Ttyy(axial yelow) in the given ratio