Competitive Exams: Revision Terminology Part 9

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• Light Dark forms (Both belong to one sp. Now as 2 forms – typical & carbonaria of B. betularia)

• Hybrid breakdown – when offspring of hybrids are infertile

• Cell anemia – glutamic acid is replaced by valine in the 6 Beta position of autosomal recessive lethal gene = 0.4 frequency of carrier in population of 200 individual is p² + 2pq +q² = 1 die due to lethal So 2pq = 2 x 0.6 x 0.4 = 0.48 and N = 200, So freq. of carrier = 0.48 x 200 = 96

• Hot spots – sites which are more mutable then other sites (Benzer) e.g. smethyl Cytosine residues

• More closely related sexual partners less are variations in their off springs.

• Classical / forward genetics – study of phenotype, analysis & isolation of concerned genes & study of DNA sequence comprising genes.

• Reverse genetics – if we start DNA Seq. study from phenotypic effect of which we do not know & then introduce in some animal to study its phenotypic effect.

• Blending of inheritable chromosome is the intermingling of heredity material of both offspring’s.

• Mendel’s success – pea easy to cultivate, naturally self-pollinated, artificially cross-pollinate.

• Mendel’s success – sharply defined inherited differences in difference varieties, only one variable at a time

• In rr seeds in small DNA Fragment interferes with SBE – 1 so starch in not formed and it accumulates as sugar – causer high osmotic pressure lead to shrinkage & wrinkling.

• Dihydric cross - inheritance of seed color is independent of seed shape.

• Homozygous - condition in which only one allele is present of a pair

• Mendel used element for factor -> gene

• Genotype exhibiting difference phenotype under difference environmental conditions – Individual norm of reaction

• Same environment & genotype but phenotype differ due to difference in internal environment = Developmental noise

• 2 different genotype produce same phenotype due to different environment & have difference genotype = phenocopies of each other

• If a dwarf plant introduced tall by gibberellin acid then too it would behave as dwarf genetically.

• In haploid organism – chromosome are governed only by one allele then law of dominance & Segregation do not apply.

• Locus = position of allele on chromosome

• Back cross Tt X any parent

• Test cross Tt X recessive (tt) Phenotype = 1 : 1 : 1 : 1

• Hugo – de Vries (Dutch) cosrrens(Germany) Tschermark (Austrian) -> Mendel’s work as principles & coined term factor

• Bateson – 1^st announced Mendel’s work in England (poultry, rabbit, sweet pea)

• Bateson coined homozygous, heterozygous, allomorphs – “ Mendel’s principle of heredity”

• Nageli advised Mendel to work on Hieracium (But he failed) seeds produced without pollination

• Mendel = 1^st genetic surgeon

  Genotype and Phenotype

  Comparison of Genotype and Phenotype based on gene pairs

  No Of gene pair	Phenotype	Genotype
  1	2	3
  2	4	9
  3	8	27

• Genetic markers => Alleles.

• Albinism = autosomal recessive mutation. If 1^st child of a normal pair in albino what is the is the probability of 2^nd child for albino = 25% (due to recessive chromosome so only homozygous condition will show albinism)

• Tt x Tt -> tt(25%) = answer

• 1^st child is independent of the 2^nd child

• What would be proportion of Tt Yy Ss Dd Ee from a cross

• Tt Yy Ss Dd Ee X Tt Yy Ss Cc Dd Ee

• Answer: of progeny will be

• TT, yy, Ss, Cc, dd, Ee.

• x x x x x = answer