Question

Same problem again: In corn (Zea mays), a dominant gene c produces colored kernels and its recessive allele c produces colorless kernels. Another dominant gene, sh produces full kernels while its recessive allele, sh, produces shrunken kernels. Waxy endosperm is controlled by a recessive gene, wx, while normal endosperm is produced by wx". A testcross between a triply heterozygouse plant and a shrunken, colorless, waxy plant produces the progeny below. phenotype (allele) csh" wx Csh wx #offspring 125 18 300 <sh wx" c sh wx c# sh" wx+ c+ sh wx* 115 Csh WX 280 What would the parental chromosomes look like in the correct order? osh+ C WX+ and sh C+ wx Oc sh+ wx and c sh wx+ Oc+ sh wx and c+ sh+ wx+ sh cwx and sh+ C+ wx+

Answer 1

Page phenotype Lauece) offspring 129 c sht wa | си ung ct sht whe c sh wat ct sh wa ct sht wat ct sh wat c sht worset 18 12 bg 200 22 6 7 8 Total 15 2 go Recombinant frequency : /R6) = No. of Recombinants" - Total no. of offsprings Тиолоlея Fiud uр хосомыири. ура со it аѕѕumе thе чеицю DEbe linked Parents etc. sht shwxt wir ac shsh wx wx. а) Иetoo7ч ош Кесеѕѕivе Родеиц але рrоduсеd аѕ аvеи и I the table above. | ТЕ Иe 3 четец и е де likea aho in which the different phenotypes. were produced would be l:1:1:1:1:1:1:1 However, what is observed deviates From tnik Kaho

To determine the ordes of genes we must find their recombinlaut Frequency uourcu Роля Срби dls prop uuuts (m.u) 11 : 1 ми We must consides a single pair of genes! at a tine. Тие ракоид Cox P Qи од с' aud gь? have o qe c+gh аnd сh Кисе е "шеtex079qote up a <tabushod bу шg que cor Buаhои и хирольuout products would be 'c.sht' and 'ct sh' Тице сопсытмаһоих сои be oциa u реагии шоиье 1', 'с' '1''g' Вk = No. 2. 0 рокіиви о т 1% o. o o pues Ара" = 12S + 300 + + 280 x 100 1 ООО 82 .. . 92 м.. о) и Аргириаик Fox a qo ch'aud up would be shunt and shtua ( 0 nubiyahoл олг розшу ишмье I' '3 '4', '1' RF - 129 + 12 + 68 + 11, хот тоого - 380 x loo = 38 ) o = 38 ми.

tsh wr. bo 82 muag wort 38 mu Rooid

Since the Rf value for the genes c and sh is 82, these genes are not linked (Rf>50 = not linked). Thuse these genes might be located on different chromosomes. Further, 82 m.u. is the distance between these genes. Similarly, since the Rf of the genes sh and wx is 38% (<50) , these genes are linked and located on the same chromosomes. Hence the order of the genes is c.sh.wx.