sao_thuy_tinh_247
Junior Member
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[FONT=.VnTime]C©u 15: Cho ph¶ hÖ sau, trong ®ã alen g©y bÖnh (kÝ hiÖu lµ a) lµ lÆn so víi alen b×nh thêng (A) vµ kh«ng cã ®ét biÕn xÈy ra trong ph¶ hÖ nµy.<o></o>[/FONT]
[FONT=.VnTime]ThÕ hÖ<o></o>[/FONT]
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[FONT=.VnTime]1 2<o></o>[/FONT]
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<v:line id=_x0000_s1041 style="Z-INDEX: 16; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" from="340pt,4.35pt" to="340pt,31.35pt"></v:line><v:rect id=_x0000_s1039 style="MARGIN-TOP: -0.15pt; Z-INDEX: 14; LEFT: 0px; MARGIN-LEFT: 357.5pt; WIDTH: 9pt; POSITION: absolute; HEIGHT: 9pt; TEXT-ALIGN: left"></v:rect><v:line id=_x0000_s1040 style="Z-INDEX: 15; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" from="321pt,4.35pt" to="357pt,4.35pt"></v:line><vval id=_x0000_s1034 style="MARGIN-TOP: -0.15pt; Z-INDEX: 9; LEFT: 0px; MARGIN-LEFT: 311.5pt; WIDTH: 9pt; POSITION: absolute; HEIGHT: 9pt; TEXT-ALIGN: left"></vval><vval id=_x0000_s1033 style="MARGIN-TOP: -0.15pt; Z-INDEX: 8; LEFT: 0px; MARGIN-LEFT: 175.5pt; WIDTH: 9pt; POSITION: absolute; HEIGHT: 9pt; TEXT-ALIGN: left"></vval><v:rect id=_x0000_s1032 style="MARGIN-TOP: -0.15pt; Z-INDEX: 7; LEFT: 0px; MARGIN-LEFT: 261pt; WIDTH: 9pt; POSITION: absolute; HEIGHT: 9pt; TEXT-ALIGN: left" fillcolor="black"></v:rect><v:rect id=_x0000_s1031 style="MARGIN-TOP: -0.15pt; Z-INDEX: 6; LEFT: 0px; MARGIN-LEFT: 3in; WIDTH: 9pt; POSITION: absolute; HEIGHT: 9pt; TEXT-ALIGN: left"></v:rect>[FONT=.VnTime]II<o></o>[/FONT]
[FONT=.VnTime]1 2 3 4 5<o></o>[/FONT]
<v:line id=_x0000_s1049 style="Z-INDEX: 24; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" from="355pt,3.8pt" to="355pt,12.8pt"></v:line><v:line id=_x0000_s1048 style="Z-INDEX: 23; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" from="318.5pt,3.3pt" to="318.5pt,12.3pt"></v:line><v:line id=_x0000_s1050 style="Z-INDEX: 25; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" from="387pt,3.8pt" to="387pt,12.8pt"></v:line><v:line id=_x0000_s1047 style="Z-INDEX: 22; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" from="4in,3.8pt" to="4in,12.8pt"></v:line><v:line id=_x0000_s1042 style="Z-INDEX: 17; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" from="4in,3.8pt" to="387pt,3.8pt"></v:line>[FONT=.VnTime]<o></o>[/FONT]
<v:rect id=_x0000_s1044 style="MARGIN-TOP: 0.05pt; Z-INDEX: 19; LEFT: 0px; MARGIN-LEFT: 383pt; WIDTH: 9pt; POSITION: absolute; HEIGHT: 9pt; TEXT-ALIGN: left" fillcolor="black"></v:rect><v:rect id=_x0000_s1043 style="MARGIN-TOP: 0.05pt; Z-INDEX: 18; LEFT: 0px; MARGIN-LEFT: 351pt; WIDTH: 9pt; POSITION: absolute; HEIGHT: 9pt; TEXT-ALIGN: left"></v:rect><vval id=_x0000_s1046 style="MARGIN-TOP: 0.05pt; Z-INDEX: 21; LEFT: 0px; MARGIN-LEFT: 315pt; WIDTH: 9pt; POSITION: absolute; HEIGHT: 9pt; TEXT-ALIGN: left" fillcolor="black"></vval><vval id=_x0000_s1045 style="MARGIN-TOP: 0.05pt; Z-INDEX: 20; LEFT: 0px; MARGIN-LEFT: 283.5pt; WIDTH: 9pt; POSITION: absolute; HEIGHT: 9pt; TEXT-ALIGN: left"></vval>[FONT=.VnTime]III.<o></o>[/FONT]
[FONT=.VnTime]1 2 3 4 <o></o>[/FONT]
[FONT=.VnTime]a. ViÕt c¸c kiÓu gen cã thÓ cã cña c¸c c¸ thÓ thuéc thÕ hÖ I vµ III.<o></o>[/FONT]
[FONT=.VnTime]b. Khi c¸ thÓ II.1 kÕt h«n víi c¸ thÓ cã kiÓu gen gièng víi II.2 th× x¸c suÊt sinh con ®Çu lßng lµ trai cã nguy c¬ bÞ bÖnh lµ bao nhiªu? ViÕt c¸ch tÝnh.<o></o>[/FONT]
[FONT=.VnTime]a. CÆp bè mÑ sè II<SUB>4</SUB> vµ II<SUB>5</SUB> ®Òu b×nh thêng nhng sinh con cã ®øa bÞ bÖnh chøng tá gen quy ®Þnh bÖnh n»m trªn NST thêng (kh«ng n»m trªn NST giíi tÝnh).<o></o>[/FONT]
[FONT=.VnTime]KiÓu gen cña c¸c c¸ thÓ: I<SUB>1</SUB> lµ aa I<SUB>2</SUB> lµ Aa (v× sinh con II<SUB>3</SUB> bÞ bÖnh.<o></o>[/FONT]
[FONT=.VnTime]III<SUB>1</SUB> vµ III<SUB>3</SUB> cã thÎ lµ AA hoÆc aa. III<SUB>2</SUB> vµ III<SUB>4</SUB> lµ aa.<o></o>[/FONT]
[FONT=.VnTime]b. C¸ thÓ II<SUB>1</SUB> vµ c¸ thÓ II<SUB>2</SUB> ®Òu cã kiÓu gen Aa (v× hä lµ nh÷ng ngêi b×nh thêng vµ bè cña hä bÞ bÖnh)<o></o>[/FONT]
[FONT=.VnTime]- X¸c suÊt ®Ó sinh con bÞ bÖnh lµ [/FONT]<v:shape id=_x0000_i1035 style="WIDTH: 12pt; HEIGHT: 30.75pt" type="#_x0000_t75" ole=""><v:imagedata src="file:///C:\DOCUME~1\THUXIN~1\LOCALS~1\Temp\msohtml1\01\clip_image040.wmz" o:title=""></v:imagedata></v:shape>[FONT=.VnTime]x[/FONT]<v:shape id=_x0000_i1036 style="WIDTH: 12pt; HEIGHT: 30.75pt" type="#_x0000_t75" ole="">[FONT=.VnTime] <v:imagedata src="file:///C:\DOCUME~1\THUXIN~1\LOCALS~1\Temp\msohtml1\01\clip_image042.wmz" o:title=""></v:imagedata>[/FONT]</v:shape>[FONT=.VnTime]= [/FONT]<v:shape id=_x0000_i1037 style="WIDTH: 12pt; HEIGHT: 30.75pt" type="#_x0000_t75" ole=""><v:imagedata src="file:///C:\DOCUME~1\THUXIN~1\LOCALS~1\Temp\msohtml1\01\clip_image043.wmz" o:title=""></v:imagedata></v:shape>[FONT=.VnTime].<o></o>[/FONT]
[FONT=.VnTime]- X¸c suÊt ®Ó sinh con trai lµ 1/2. <o></o>[/FONT]
[FONT=.VnTime]VËy x¸c suÊt ®Ó cÆp vî chång nµy sinh ®îc mét con trai bÞ bÖnh lµ [/FONT]<v:shape id=_x0000_i1038 style="WIDTH: 12pt; HEIGHT: 30.75pt" type="#_x0000_t75" ole=""><v:imagedata src="file:///C:\DOCUME~1\THUXIN~1\LOCALS~1\Temp\msohtml1\01\clip_image045.wmz" o:title=""></v:imagedata></v:shape>[FONT=.VnTime]x[/FONT]<v:shape id=_x0000_i1039 style="WIDTH: 12pt; HEIGHT: 30.75pt" type="#_x0000_t75" ole="">[FONT=.VnTime] <v:imagedata src="file:///C:\DOCUME~1\THUXIN~1\LOCALS~1\Temp\msohtml1\01\clip_image046.wmz" o:title=""></v:imagedata>[/FONT]</v:shape>[FONT=.VnTime]= [/FONT]<v:shape id=_x0000_i1040 style="WIDTH: 11.25pt; HEIGHT: 30.75pt" type="#_x0000_t75" ole=""><v:imagedata src="file:///C:\DOCUME~1\THUXIN~1\LOCALS~1\Temp\msohtml1\01\clip_image047.wmz" o:title=""></v:imagedata></v:shape>[FONT=.VnTime].<o></o>[/FONT]
Câu này hình như có hai trường hợp, thêm trường hợp gen nằm trên đoạn tương đồng XY nữa , vẫn thỏa mãn mà.