IMPORTANT TERMS OF PRINCIPLES OF INHERITANCE AND VARIATION

IMPORTANT TERMS OF “PRINCIPLES OF INHERITANCE AND VARIATION”

IMPORTANT TERMS OF “PRINCIPLES OF INHERITANCE AND VARIATION”

 

GENEITCS:- The study of heredity and variation.

HEREDITY:- The Study of Transfer of characters from one generation  to another generation.

INHERITANCE:- The process of transfer of characters from one generation to another generation.

VARIATION:- The degree by which offspring differ from their parents

IMPORTANT TERMS OF PRINCIPLES OF INHERITANCE AND VARIATION

  • Physical unit of inheritance = GENE
  • Chemical unit of inheritance = DNA
  • Gene is functional segment of DNA.
  • Father of Modern Genetics = BATESON
  • Father of Human Genetics = A.GARROD
  • GARROD discovered firstly Alkaptonuria later discovered Phenylketonuria.

 

TYPES OF VARIATION:-

  • Somatic variation:-
  • Changes in normal body cells.
  • Do not transfer from one generation to next generation.
  • Acquired (Non-Inheritance).
  • No role in Evolution.

 

  • Germinal variation:-
  • Changes in Germinal cells.
  • Can pass from one generation to next generation
  • By Birth (inherited)
  • Play important role in Evolution.

 

IMPORTANT TERMS :-

  • ALLELE OR ALLELOMORPH:-
  • Alternate form of Gene
  • A pair of contrasting trait.
  • All alleles are gene but all gene are not allele.

 

  • HOMOZYGOUS:-
  • The presence of similar alleles of a character in diploid organisms.
  • Examples:- TT, tt, RR, rr, etc.

 

  • HETEROZYGOUS:-
  • The presence of dissimilar alleles of a character in diploid organisms.
  • Examples:- Tt, Rr, Yy, etc.

 

  • HEMIZYGOUS:-
  • The presence of Single allele of a character in diploid organisms.
  • Examples:- T, Y, t, y, etc.

 

  • PHENOTYPES:-
  • External features/ characters.
  • Examples:- Tall, Dwarf, Violet, White, etc.

 

  • GENOTYPES:-
  • Internal Features/ characters.
  • Examples:- Tt, TT, tt, etc.
  • PHENOCOPY:-
  • Different genotype representing Similar Phenotype.
  • Examples:- TT or Tt represent tall (TT or Tt = Tall).

 

  • PURELINE:-
  • Obtained by selfing/ self-cross for several generations.
  • Trait obtained in all generations will be same.

 

  • MONOHYBRID CROSS:-
  • When one pair of contrasting trait taken in cross then, that type of cross is called monohybrid cross.
  • Examples:- tall (TT) × dwarf (tt)

 

  • DIHYBRID CROSS:-
  • When two pair of contrasting trait taken in cross then, that type of cross is called Dihybrid cross.
  • Examples:- RRYY(round yellow) × rryy(wrinkled green)

 

  • DOMINANT:-
  • Suppresses other character.
  • Examples:- tall, round seed, etc.

 

  • RECESSIVE:-
  • Suppressed character.
  • Examples:- dwarf, green seed, etc.

 

  • TEST- CROSS:-
  • Hybrid crossed with recessive parent.
  • Examples:- Tt × tt

 

  • OUT- CROSS:-
  • Hybrid crossed with dominant parent.
  • Examples:- Tt × TT

 

  • RECIPROCAL CROSS:-
  • Examples:- TT(male) × tt(female)

TT(female)× tt(male)

 

  • CHARACTER:-
  • Any morphological, anatomical, physiological expressions are called characters.

 

  • TRAIT:-
  • Different forms of character.

 

  • CONTRASTING TRAIT:-
  • Different trait
  • Examples:-
     CHARACTER    DOMINANT/ RECESSIVE
SEED SHAPE        ROUND/ WRINKLED
SEED COLOUR      YELLOW/ GREEN
FLOWER COLOUR         VIOLET/ WHITE
POD SHAPE       FULL/ CONSTRICTED
POD COLOUR       GREEN/ YELLOW
FLOWER POSITION       AXIAL/ TERMINAL
STEM HEIGHT        TALL/ DWARF

 

  • GENOME:-
  • The sum total of all gene present in haploid set of chromosome of an organisms.

 

  • GENE POOL:-
  • The sum total of all gene present in haploid set of chromosome of population.

 

  • INBREEDING:-
  • Cross between closely related individuals of same species.

 

  • OUT-BREEDING:-
  • Cross between distantly related individuals of same species.

 

  • HYBRID VIGOUR:-
  • Offspring are superior to their parent.

 

  • PLEIOTROPHY:-
  • If one gene expresses more than one character.

 

  • POLYGENIC:-
  • If more than one gene are responsible for a character.

 

  • MULTIPLE ALLELISM:-
  • If more than two alleles for a character
      PHENOTYPE GENOTYPE
         A      IA IA / IA I0
          B      IB IB/ IB I0
        AB      IA IB
         O       I0 I0

IMPORTANT TERMS OF PRINCIPLES OF INHERITANCE AND VARIATION

 

MUTATION:-

  • Sudden change in DNA/ chromosome/ gene.
  • May be large, small, Harmful, Beneficial.
  • Inheritable (Germinal cell), Non-Inheritable (Somatic cell).
  • Change in single base pair is called point mutation.
  • Due to mutation, number of chromosomes may be increases or decreases.
  • Mutation causing agent are called Mutagens.
  • Sickle cell anemia is a point mutation

 

I HOPE, THESE (IMPORTANT TERMS OF “PRINCIPLES OF INHERITANCE AND VARIATION”) ARE VERY  USEFUL FOR YOU…. AND YOU CAN ASK QUESTION RELATED TO THESE CHAPTER …

 

AND ALSO YOU CAN READ  ABOUT PLATELETS AND CLOTTING FACTOR..

 

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