flower color in pea plants purple phenotype appearance has genotype actual

Flower color in pea plants purple phenotype

This preview shows page 15 - 23 out of 187 pages.

flower color in pea plants: purple phenotype (appearance) has genotype (actual alleles): PP or Pp Genotype and Phenotype Because of the different effects of dominant and recessive alleles, an organism s traits do not always reveal its genetic composition Therefore, we distinguish between an organism s phenotype : physical appearance and its genotype : genetic makeup
Testcross Use to determine genotype of individual that has dominant phenotype . By crossing a homozygous recessive individual with the unknown, any recessive alleles will be revealed. Used as a tool for geneticists
Sperm 1 / 4 1 / 4 1 / 4 1 / 4 1 / 4 1 / 4 1 / 4 1 / 4 9 / 16 3 / 16 3 / 16 1 / 16 YR YR yr yr Yr Yr yR yR YYRR YYRr YyRR YyRr YYRr YYrr YyRr Yyrr YyRR YyRr yyRR yyRr YyRr Yyrr yyRr yyrr dihybrid cross: following two traits Punnett square Cross: YyRr x YyRr gametes gametes Egg Yellow: 12 green: 4 Yellow to green ratio: 3:1 Round: 12 wrinkled: 4 Round to wrinkled ratio: 3:1 Reveals independent assortment as each trait maintains the expected ratio Overall phenotypic ratio 9:3:3:1 genotypic ratio 1:2:1:2:4:2:1:2:1 9 (yellow/round):3(yellow/wrinkled):3(green/round):1(green/wrinkled)
The Law of Independent Assortment seed color: yellow (dominant) green (recessive) seed shape: round (dominant) wrinkled (recessive) dihybrids Crossing two, true-breeding parents differing in two traits produces dihybrids in the F 1 generation, heterozygous for both characters A dihybrid cross- a cross between F 1 dihybrids, can determine whether two characters are transmitted to offspring as a package or independently Mendel identified his second law of inheritance by following two traits at the same time
If on different chromosomes, each pair of alleles segregates independently of other pairs of alleles during gamete formation Genes located near* each other on the same chromosome tend to be inherited together (* too close for recombination to occur between them). The Law of Independent Assortment Meiosis Gametes with independent assortment of chromosomes Parental cell with 3 pairs of homologous chromosomes
Probability- a measure of how likely it is that an event will occur When tossing a coin, the outcome of one toss has no impact on the outcome of the next toss In the same way, the alleles of one gene segregate into gametes independently of another gene s alleles- with no impact on the segregation of anothe
the probability that 2 independent events will occur together is the product of their individual probabilities The probability of flipping a coin and getting two “tails” in a row = the product of the individual probabilities.

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture