Law of Independent Assortment

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???????????????????????????????????????? Law of
Independent Assortment
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Dihybrid cross
Parent
RRYY
rryy
F1 (first falial)
RrYy
F2 (second falial)
R_Y_
R_yy
rrY_
rryy
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Testcross
???????????????????????????homozygous dominant
???? heterozygote ???????????????? homozygous
recessive
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• ????????????????? ??????????????????????????
  homozygous dominant(AA)

• ???????????????? 1 ??? ??????????????????????????
  heterozygote (Aa)

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??????????????(genotypes)

• Punnett square
• Branching

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Punnett square
RrYy x RrYY
Parent
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???
F1
???????

• ????????????????(gametes)????????????
• ????????????? punnett square

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Genotype RrYy
Genotype RrYY
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Punnett square
RrYy x RrYY
???
Parent
???
F1
Phenotype R_Y_ 3/4 rrY_ 1/4
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Branching
RrYy x RrYY
Parent
???
???
F1
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RrYy X RrYY
Yy X YY 1/2YY 1/2Yy
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Branching
Phenotype R_Y_ 3/4 rrYy 1/4
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• Allele or Allelomorph
• Chromatin
• Chromosome
• Chromatid
• Gene
• Genotype
• Polygene
• Phenotype

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• Allele a shorthand form of allelomorph, one of
  a series of possible alternative forms of a
  given gene differing in DNA sequence, and
  affecting the functioning of a single product
  (RNA and/or protein). If more than two alleles
  have been identified in a population, the locus
  is said to show multiple allelism.
• Gene a hereditary unit that, in the classical
  sense, occupies a specific position (locus)
  within the genome or chromosome a unit that has
  one or more specific effects upon the phenotype
  of the organism a unit that can mutate to
  various allelic forms a unit that recombines
  with other such units.
• Polygene one of a group of genes that together
  control a quantative character.

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• Chromatin the complex of nucleic acids (DNA
  and RNA) and proteins (histones and nonhistones)
  comprising eukaryotic chromosomes.
• Chromosome 1. In prokaryotes, the circular DNA
  molecule containing the entire set of genetic
  instructions essential for life of the cell. 2.
  In the eukaryotic nucleus, one of the threadlike
  structures consisting of chromatin and carrying
  genetic information arranged in a linear
  sequence.
• Chromatids the two daughter strands of a
  duplicated chromosome that are joined by a
  single centromere. Upon the division of the
  centromere, the sister chromatids vecome separate
  chromosomes.

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• Genotype the genetic constitution of an
  organism, as distinguished from its physical
  appearance (its phenotype).
• Phenotype the observable properties of an
  organism, produced by the genotype in conjunction
  with the environment.
• Locus (plural loci) the position that a gene
  occupies in a chromosome or within a segment of
  genomic DNA.
• Genome a term used to refer to all of the genes
  carried by a single gamete ( I.e., by a single
  representative of each of all chromosome pairs).

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??? x ??? 1 ???????????????? x
???????????????? 2 ???????????????? x
???????????????? 3 ???????????????? x
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3/4 ???????????????? 1/4????????????????
6/16???????????????? 2/16??????????????? 6/16?????
??????????? 2/16???????????????
1/4???????????????? 1/4??????????????? 1/4????????
???????? 1/4???????????????