i phoi cua quy luat tinh troi. Quy iTdc: A: Cay cao; a: Cay tha'p
dm nang lij On va luy$n thi Sinh hpc - Phung Duy Ddng
Ta CO cay thap chiem ti le: ~ = = ^x— giao tur chiem ti le — c6
12 6 2 6 6
the la giao tuf cua cay 2n, cung c6 the la giao tuf cua cSy da bpi 1 3^ SPdo lai: 1. F, - G(F,) The he lai AAaa -AA:—Aa:-aa 6 6 6 — AAA:—AAa: 12 12 X Aa \ f 1 1 X - A : - / U 2 4 4 —AAa:—j 12 12 _1_ 12' '12'
Kieu hinh : 11 cay cao : 1 cay thap.
2. F| : AAa x Aa
G(F,) — AA:—Aa:—A:—a 6 6 6 6 i A : l a
U 2 ,
1 1 2 2 2 2 1 1
The he lai : —AAA:—AAa:—AAa:—Aaa:—AA:—Aa:—Aa:—aa 12 12 12 12 12 12 12 12
Kieu hinh : 11 cay cao : 1 cay thap.
: Aaa x 3. F, G(F,) The" he lai AAaa ^ 2 ^ 1 1 ^ 2 — Aa:—aa:—A:—a -AA:—Aa:—aa 1 1 16 6 6 , Kieu hinh 4. F, G(F,) 2 8 2 1 — A AAa:—AAaa:—Aaaa:—AAaa: 36 36 36 36 4 1 1 4 — Aaaa:—aaaa:—AAA:—AAa: 36 36 36 36 J_Aaa:AAAa:AAaa:-laaa. 36 36 36 36
^ cay cao : ^ cay thap = cay cao : ^ cay thap. Aaa
1 1 X
— Aa:—aa:—A:-a 6 6 6 6 - A A : - A a : - A : - a ^ A A 2 ^ 2 1 AAa 6 6 6 6 2 4 4 2
The he lai: —AAAa:—AAaa:—AAa:—Aaa: 36 36 36 36
-LAAaa:AAaaa:AAaa:±aaa:
36 36 36 36
AAAa:±Aaa:i-Aa:i-aa. 36 36 36 36
Kieu hinh 33 . 3 . 11 ^ 1 ^ 1
— cay cao : — cay thap = — cay cao : — cay thap.
36 36
Cty TNHH MTV DVVH Khang Vigt
5. F, G(F,) G(F,) The he lai AAaa 4 1 — AA: —Aa:—aa 6 6 6 Kieu hinh 6. F, G(F,) The he lai Aaaa x 3 3 ^ ^ — Aa:-aa v6 6 3 12 3 — AAAa: — AAaa:—Aaaa i ! ' ! 36 36 36 3 A A 12 3 — AAaa:—AAaa:—aaaa 36 36 36 33 3 ^ 11 ^
— cay cao : — cay thap = — cay cao 36 36 12 ^
Aaaa x AAa
^ cay thap. "'I'
12 ^3 A 3 ^ ^3 A 3 ^ - A a —aa x u 6 y -AA:—Aa:—A:—a 6 6 6 6 — AAAa:—AAaa:—AAa:—Aaa 36 36 36 36 —AAaa:—Aaaa:—Aaa:—aaa. 36 36 36 36
Kieu hinh — cay cao : — 33 , 3 36 ' 36 cay thap = — cay cao : — cay thap. 12 11 12
Vidu6:
Cho bie't A: Qua ngot, a: Qua chua. Dem lai cac cay ti? bpi vdi nhau cho ket
qua d F| nhiT sau:
a) Tmyng hap 1: Phan li kieu hinh 3 qua ngot: 1 qua chua.
b) Tmyng hap 2: Xuat hien 350 cay qua ngot trong to'ng so' 420 cay. ' HUdngddn HUdngddn
a) TriTdng hPp 1: Cay qua chua chiem ^ ^ ^ Do do: P : Aaaa x Aaaa Do do: P : Aaaa x Aaaa
b) Tru'ctng hPp 2: Cay qua ngot chiem ti 16 = 7
420 6
Do do cay qua chua chiem ti le - = - x 1 q ;
6 6 : ,
=> P : AAaa x aaaa
Liiu y: Ve lai cac the dot bien c6 ra't nhieu bai tap, nhifng deu thupc 2 loai: 1. Loai thvtnhdt: Biet cong thiJc lai, tim kel qua lai.
PhiTdng phap giai loai toan nay nhU" sau:
a) TriTdc het phai xac dinh du-pc kieu gen cua bo me (P) tCf do xac dinh c6 bao
dm nang tij On va luygn thi Sinh hgc - Phung Duy oa'ng
b) Xac dinh so loai giao tu" c6 kha nang song va thanh phan gen cua moi loaj giao tur diTOc hmh thanh tu" bo va me (Cd the 4n chi c6 giao tit 2n mdi c6 kha giao tur diTOc hmh thanh tu" bo va me (Cd the 4n chi c6 giao tit 2n mdi c6 kha nang song. Cd the 3n thi giao tu" n va 2n deu c6 kha nang song).
c) Cho cac loai giao tuT cua bo', me ket hdp vdi nhau (lap bang). TCf do suy
u" phan l i kieu gen va kieu hinh.
2. Lr^a/?M/ia/.-Bie't ke't qua lai, tim cong thi?c lai. Phu"dng phap giai loai toan nay nhu" sau: Phu"dng phap giai loai toan nay nhu" sau:
a) Xac dinh so kieu hinh lap chiem ti le bao nhieu ( V i du 6). HoSc tim xem
CO kieu hinh nao chi chiem mot phan trong tdng so cac phan kieu hinh dtfdc sinh
ra (xem v i du 3)
b) Xac dinh nhi?ng kieu gen nao sinh ra ti le giao tu'tren. c) Tu" do suy ra cac sd do lai va giai tijfng sd do lai. c) Tu" do suy ra cac sd do lai va giai tijfng sd do lai.
Loai 6: Giai thich cac hien ttfdng dot bien.
Vi du 1: Do dot bien nen- c6 nhiJng cd the c6 NST gidi tinh la X O hoSc XXY.
^ Cung do dot bien, c6 nguTdi c6 gen Ian nam tren NST gidi tinh X va bieu hien thanh benh mu mau.
1. M o t cap vd chong, ca 2 c6 kieu hinh binh thtfdng hp sinh mot dtfa con gai X O , bieu hien benh mii mau. X O , bieu hien benh mii mau.
Hay giai thich hien tu'dng nay.
2. M o t phu nff bieu hien benh mu mau, ket hon vdi mot ngiTdi c6 kieu hinh binh thu^dng. Hp sinh drfdc mot dtfa con trai. Neu diJa con trai nay c6 NST gidi binh thu^dng. Hp sinh drfdc mot dtfa con trai. Neu diJa con trai nay c6 NST gidi tinh la X X Y , khong bieu hien benh mii m^u hoac c6 bieu hien mil mau thi giai thich ra sao?
' Hudngddn
1. Giai thich hien tu'dng:
Quy urdc X'^: Khong bieu hien benh mii mau. X^• Bieu hien benh mii mau. Con gai X O nhan X" tCf me va O turbo.
Bo me CO kieu hinh binh thiTcfng. Sif giam phan te bao sinh due cua b d c6
hien tu'dng dot bien the di bpi. S d d o l a i :
P : X ^ X " x X ^ Y G(P) : X ^ r x X ^ Y , 0 G(P) : X ^ r x X ^ Y , 0
F, : I X ^ X ^ Y : I X ^ ^ Y : I X ^ O : I X ' O (con gai bieu hien benh). 2. Con trai X X Y cd va khong bieu hien bpnh mii mau.
Co the giai thich bang sd do sau:
Saddlail: P : X ^ X ^ x X ^ Y
G(P) : X" x X ^ Y , 0 ^ F, : I X ^ X ' - Y : IX^O.
(Con trai X'^X'Y khong bieu hien benh mii mau) 114 ,.
Cty TNHH MTV DWH Khang Vigt
Sadolail: P G(P) F, X"X" X X ^ Y x " x ^ o x ^ Y ^ ,v..-^ IX^X^Y : IX^X^X" : 1X^0 : 1 0 Y . ' , (Con trai X^X^Y CO bieu hien benh mil mau).
Vidu 2: M o t cap vd chong sinh d^dc 2 ngu'di con:
Dtfa thiJ nhat c6 kieu hinh binh thiTdng, difa thu" hai c6 bieu hien benh Dao. Cap vd chong nay c6 nhCng ban khoan:
1. Tai sao lai sinh ra diJa con thu" hai nhu* vay? Do vd hay chong?
2. Neu sinh con ni^a thi diJa tre sinh ra c6 bieu hien bdnh Dao hay khong? 3. Ngu'di bi benh Dao c6 kha nang sinh con hay khong? Neu c6 thi con hp se 3. Ngu'di bi benh Dao c6 kha nang sinh con hay khong? Neu c6 thi con hp se nhiT the nao? Hay giai dap ban khoan noi tren.
Hudngddn '
1. DiJa con binh thudng la do sif tai to hdp gii?a triJng binh thifdng (n) vdi tinh trung binh thtfdng (n). trung binh thtfdng (n).
DiJa con khong binh thiTdng (bieu hien benh Dao) la do trong qua trinh giam phan phat sinh giao tuT cap NST thur 21 khong phan l i nen da tao thanh 2 loai giao tuf: Mot loai c6 ca 2 chiec cua cap 21 (n + 1). mot loai k h o n g chuTa chiec nao cua cap 21 (n - 1). Khi thu tinh, giao tuf thifa 1 chiec cua cSp 21 ket hdp giao tuf binh thirdng tao thanh hdp tuf cap 21 cd 3 chiec phat trien thanh benh Dao.
Su" giam phan khong binh thu'dng c6 the tijf te bao sinh tinh triing hay te bao sinh triJng. V i vay nguyen nhan gay ra benh c6 the do vd ho^c chong.
Tuy nhien, nhiTng nghien ciJu tren the gidi cho bie't t i le bi benh Dao tang len
Cling vdfi tuoi ngu'di me do sif giam phan d ngtfcli phu nif l<3n tuoi de xay ra khong binh thtfdng.
f 2. Neu sinh diJa con niJa thi cung c6 kha nang bi benh Dao, nhu'ng ra't hiem, vi tan so' dot bien rat be. vi tan so' dot bien rat be.
3. Ngu'di bi benh Dao thtfdng v6 sinh, do sir giam phan gSp nhieu trd ngai trong qua trinh tiep hdp, phan li. Tuy nhien cung c6 the c6 kha nang sinh con. TnTdng hdp qua trinh tiep hdp, phan li. Tuy nhien cung c6 the c6 kha nang sinh con. TnTdng hdp nay khi giam phan se hinh thanh cac loai giao tuf: n, n + 1, n + 2, n - 1.
Chi CO giao tu" n ket hdp vdi giao tuf binh thiTdng se sinh con binh thu'dng, con
cac loai giao tufkhac se khong tao ra con binh thifdng diTdc (bi dot bien lech bpi). Nhtf vay con cua hp c6 den 75% bi dot bien lech bpi.
Vi du 3: M e n Hb^ gay benh thie'u mau hong cau hinh l i e m alen H b ' quy
\h kieu hinh binh thifdng. K i e u gen di hdp Hb^Hb' gay benh thie'u mau \g cau hinh l i e m nhe.
1. M o t cap vd chong sinh diTdc mot diJa con bieu hipn benh thie'u mdu hong cau hinh liem nhe. Kieu gen cua b d me c6 the nhuf the' nao? cau hinh liem nhe. Kieu gen cua b d me c6 the nhuf the' nao?
2. Neu cap vd chong sinh diTdc mot dtfa con c6 kieu hinh binh thtfdng, kieu