Bai cika dominance - shi ne sakamakon da hulda da alleles na daya gene

Bai cika dominance - musamman irin hulda gene allele, cikinsa da weaker recessive hali ba za a gaba daya suppressed rinjaye. A daidai da dokokin, bude Mendel, rinjaye gaba ɗaya cike da furcin recessive. The bincike nazari pronounced contrasting dabiu a shuke-shuke da wani buɗi na ko dai rinjaye ko recessive allele. A wasu lokuta, Mendel da fuskantar da gazawar da dokokin, amma bai bayyana su.

Wani sabon tsari na gado

Wani lokaci, a sakamakon tsallaka zuriyarsa gaji matsakaici ãyõyi, wanda ba su ba a cikin homozygous nau'i na iyaye gene. Bai cika dominance ya ba a cikin na ra'ayi na'ura jinsi zuwa farkon XX karni, a lõkacin da aka sake gano Mendel ta dokokin. Sa'an nan, da yawa na halitta da masana kimiyya da za'ayi kayyade gwaje-gwajen da kayan lambu da dabbobi abubuwa (tumatir, legumes, hamsters, beraye, da 'ya'yan itace kwari).

Bayan cytological tabbatarwa a 1902, Walter Sutton Mendelian alamu na watsa akida, da kuma hulda da ãyõyi fara bayyana matsayin da hali na chromosomes a cikin cell.

A wannan 1902 Cermak Correns bayyana al'amarin a lokacin da, bayan tsallaka shuke-shuke da farin da kuma ja corolla a cikin zuriyarsa sun furanni na ruwan hoda launi - bai cika dominance. Wannan nuni da hybrids (genotype Aa) halayyar wanda yake tsaka-tsaki dangi zuwa homozygous rinjaye (AA) da kuma recessive (aa) phenotypes. A irin wannan sakamako da aka bayyana ga mutane da yawa jinsunan flowering shuke-shuke: snapdragons, hyacinth, kyau da dare, strawberries.

Bai cika dominance - wani dalilin da canji na enzymes aiki?

Ginshikai na bayyanar da uku embodiment fasalin za a iya bayyana daga matsayin na ayyuka na enzymes wanda suke da sunadarai ta hanyar yanayi da genes ƙayyade da furotin da tsarin. A shuka da mai homozygous rinjaye genotype (AA) enzymes zai zama isa da adadin pigment zai dace da kudi don maida bata da cell sap.

Homozygotes da recessive alleles (aa) pigment kira karye whisk zauna uncolored. A cikin hali na tsaka-tsaki heterozygous genotype (Aa), mai rinjaye gene har yanzu ba wani adadin na enzyme alhakin pigmentation, amma ba isa ga haske cikakken launuka. Sai dai da launi na "rabin."

ÃyõyinSa gaji da matsakaiciyar irin

Irin wannan bai cika gado sa ido sosai a kan wani m magana da cututtuka:

1. A launi tsanani. William Bateson, ya haye baki da fari hens Andalusian irin su jinsi tare da azurfa gashinsa. A definition na mutum ido Iris launi harsashi ne ma ba aiki inji.
2. A mataki na tsanani daga cututtuka. mutum gashi kuma an yi niyyar su bai cika gado hali. Genotype AA ba curly gashi, aa - mike, da kuma mutane da duka alleles da wavy gashi.
3. Da ma'auni Manuniya. alkama kunne tsawon aka gada a kan tushen da bai cika dominance.

A F2 tsara phenotypes yawan daidai da yawan genotypes cewa characterizes bai cika dominance. Test giciye domin sanin hybrids ba bukatar, saboda sun kama daban-daban daga rinjaye tsabta Lines.

Tsakiyan nonon a mararraba ãyõyi

Complete da bai cika dominance kamar gene hulda auku a daidai da ilmin lissafi dokokin na Mendel. A farkon yanayin, da rabo a cikin F2 phenotypes (3: 1) ba ta zo daidai da rabo daga zuriyarsa genotypes (1: 2: 1) kamar yadda phenotypically haduwa da AA kuma Aa alleles bayyana guda. Sa'an nan bai cika dominance - wani wasa a F2 rabbai na daban-daban genotypes da phenotypes (1: 2: 1).

A strawberry canza launi da na gada, a shekara a kan tushen da bai cika dominance. Idan ƙetare mai shuka da ja berries (AA) da kuma shuka tare da farin berries - genotype AA, ƙarni na farko na shuke-shuke duk samu zai ba da 'ya'ya tare da wani ruwan hoda launi (Aa).

Hybrids an tsallaka daga F1, F2 a karo na biyu tsara zuriyarsa samu wani aboki wanda ya zo daidai da abin da genotype: 1AA + + 2Aa 1AA. 25% na shuke-shuke na biyu ƙarni zai samar da ja da uncolored 'ya'yan itãcen marmari, 50% na shuke-shuke - m.

A irin wannan abin kwaikwaya za a lura a biyu da al'ummomi ta tsallaka m Lines da kyawawan furanni da dare corolla shunayya, da fari launuka.

Features na gado a cikin hali na mace-mace genes

A wasu lokuta, da rabo daga phenotypes na zuriya da wuya a tantance yadda kwayoyin halittu mu'amala. A karo na biyu ƙarni ta bai cika dominance tsagawa shi ya bambanta daga ran 1: 2: 1 da kuma 3: 1 - a cike. Wannan ya faru a lokacin da wani rinjaye ko recessive hali a homozygous jihar bada phenotype cewa ba jituwa tare da rayuwa (na mutuwa genes).

A astrakhan tumaki launin toka launi jariri da 'yan raguna da suke homozygous ga rinjaye allele launi, mutu saboda gaskiyar cewa wannan genotype a take ciki.

A cikin mutane, wani misali na mace-mace rinjaye nau'i na gene - brachydactyly (korotkopalost). Alama gano a cikin hali na heterozygous genotype, yayin da rinjaye homozygotes mutu a farkon matakai na fetal ci gaba.

Iya zama na mutuwa recessive alleles. Sikila anemia sa, a cikin hali na biyu recessive alleles a genotype, ta samar da erythrocytes canji. Maikacin jini ba zai iya yadda ya kamata a haɗe oxygen, da kuma 95% na yara tare da wannan anomaly aka kashe da oxygen yunwa. A heterozygotes da modified nau'i na ja da maikacin jini ba ya canzawa zuwa irin wannan har a kan viability.

Tsakiyan nonon a gaban ãyõyin mutuwa genes

A ƙarni na farko, a lokacin da ya haye AA x aa mace-mace ba za ta auku, saboda dukan zuriyar za ta yi da AA genotype. Ka ba da misalai na ãyõyin tsagawa for biyu ƙarni lokuta na mutuwa genes:

Yana da muhimmanci a fahimci cewa sakamako a lokacin da biyu da aka kona bai cika dominance, da kuma sakamako na suppressing m alama taso daga hulda da gene kayayyakin.