Animal Genetics and Breeding question bank-4
Hello vets , these are some important basic questions regarding Animal Genetics and Breeding , hope you enjoy it.
Refresh your memory....👍
Refresh your memory....👍
Animal Genetics And Breeding
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Animal Genetics and Breeding question bank-4 |
• Theory of germplasm was introduced by- August Weisman.
• Mendel studied the inheritance of seven different pairs of contrasting characters.
• % of homozygous offsprings in F2 generation of monohybrid cross is – 50
•The terms ‘genotype’ and ‘phenotype’ coined by- Johanssen
•Test to assess whether the individuals are showing dominant character due to homo or heterozygosity- Test cross
•Universally accepted Mendel’s law is- Law of Segregation
• The term ‘heterosis’ was coined by- Shull (1910)
• Genes that influence more than one phenotype trait is called –Pleiotropic genes.
• Phenotypic ratio n incomplete dominance is – 1:2:1
• Dominance involves intragenic gene suppression while epistasis involve intergenic suppression.
• ‘Yellow’ in mice is an example of- dominant lethal condition
• Genotype that is a carrier for sickle cell anemia is – Hb A /Hb S
• Expression of ancestral traits is termed as – Atavism.
• Qualitative characters like coat color, blood group etc. shows discontinuous variation, where as quantitative traits like height, weight etc. shows continuous variations.
• Alternative form of a normal gene is called- Allele
• Coat color in rabbits is an example of- Multiple allellism.
• Number of linkage groups in an orgainsim is equal to no: of chromosome pairs.
• Theory of linkage and concept of sex linked inheritance was proposed byThomas Hunt Morgan
• Rediscoverer’s of Mendelian genetics was- Tschermack, Correns and Devries.
• Complete linkage is seen in – Male Drosophila
• Sex-linked genes for hemophilia and colorblindness in man are examples of Incomplete linkage
• Strength of linkage is inversely proportional to the distance between the genes and the strength is reduced by temperature and X-rays
• Crossing over occurs between non-sister chromatids of homologous pairs of chromosomes.
• Chances of crossing over more if genes are located- farthest
• ‘Crossing over’ takes place at the tetrad stage of meosis.
• Cell division characterized by splitting of nucleus followed by that of cytoplasm is called – Amitosis.
• Spindle formation inhibition and arresting the cells in metaphase are done bycolchicine.
• Examples of mitotic poison- Colchicine, Ribonuclease and Mustard gas.
• During meosis, pairing of chromosomes occur at- Zygotene stage
• From one spermatocyte 4 haploid spermatids are formed where as one oocyte forms single ovum.
• The term ‘Chromosome’ was coined by - Waldeyer
• Chromosomal basis of heredity was proposed by- Walter. S. Sutton.
• Chromosome with centromere in terminal position is called- Acrocentric.
• Chromosomes with subterminal centromere is called- Telocentric (J-shaped)
• Interphase chromosomes which are large and visible with naked eye are calledPolytene chromosomes.
• ‘Cri-du-chat’ or ‘Cat cry syndrome’ is caused by deletion in the short arm of 5 th chromosome
• Interchange of chromosome segments in non-homologous chromosomes is calledTranslocation
• The method devised by Muller for detecting X-linked mutations in Drosophila is – CIB method.
• Classical experiments on Neurospora crassa was performed by- Beadle and Tatum.
• Substitution of a purine by a pyrimidine is called- Transversion
• Changes that involve replacement of one purine in a polynucleotide chain by another purine is called- Transitions
• Alkylating agents capable of causing mutations are- Ethyl methane sulphonate and Methyl methane sulphonate.
• Mutations caused by addition or deletion of nitrogenous based in the DNA or mRNA are known as- Frame shift mutation.
• In interphase, nucleus of cells in females a dark stained chromatin mass is observed called- Barr body.
- Please Do Comment if you find any error in the answers✅❌
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