GENETICS GENETICS AND AND

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CM N bh hCM N bh hbyby CM Nagabhushan,CM Nagabhushan,SSH JAIN PU COLLEGE,SSH JAIN PU COLLEGE,

Harapanahalli.Harapanahalli.

PART IPART – IGenetics topics.

GENETICS

MENDEL

GENETICS

MENDEL

GENETIC TERMINOLOGYLAWS OF MENDELGENETIC TERMINOLOGY

EXAMPLES

GENETICSDEVIATIONS

GENETICS

INCOMPLETE DOMINANCE

MULTIPLE ALLELISMSEX LINKAGE

X AND Y-LINKAGEX AND Y-LINKAGE

GENETICS

DISORDERS

GENETICS

DISORDERS

CHROMOSOMALCHROMOSOMALGENE DISORDERS

GENETIC TERMINOLOGYGENETIC TERMINOLOGY

Q D fi GENETICSQ.Define GENETICS.

IT IS THE STUDY OF HEREDITY & VARIATIONS.VARIATIONS.

GENETIC TERMINOLOGYGENETIC TERMINOLOGY

Q. What is a GENE ?Structural and functional Structural and functional unit of heredity responsible for the responsible for the expression of a character.

GENETIC TERMINOLOGYGENETIC TERMINOLOGY

Q. What is a HYBRID ?AN OFFSPRING OBTAINED AN OFFSPRING OBTAINED BY CROSSING 2 PARENTS DIFFERING IN ATLEASTDIFFERING IN ATLEASTONE CHARACTER.

GENETIC TERMINOLOGYGENETIC TERMINOLOGY

Q Define homozygous Q. Define homozygous condition ?

A CONDITION WHERE PAIRED GENES ARE SIMILAR ON GENES ARE SIMILAR ON HOMOLOGUES.

‘TT RR AA….’

GENETIC TERMINOLOGYGENETIC TERMINOLOGY

Q. What is heterozygous ygcondition ?

A CONDITION WHERE PAIRED GENES ARE DISSIMILAR ON HOMOLOGUES.

‘Tt Rr Aa ….’

GENETIC TERMINOLOGYGENETIC TERMINOLOGYQ. What are Homologous chromosomes ?chromosomes ?A pair of identical chromosomes where one is of paternal origin and the p gother is of maternal origin.

GENETIC TERMINOLOGYGENETIC TERMINOLOGY

Q D fi PHENOTYPE ?Q. Define PHENOTYPE ?

Externally visible Externally visible morphological character.

Ex. Purple flower colourTall plant etc.

GENETIC TERMINOLOGYGENETIC TERMINOLOGYQ. What is GENOTYPE ?Genetic make up of an individual (the sum total of individual. (the sum total of genes inherited from both the parents irrespective of the parents irrespective of whether they are expressed or not.)

TT, Tt, tt etc.

GENETIC TERMINOLOGY.Q. What is test cross ?.

Write its significance.Write its significance.A cross between F1 hybrid (of unknown genotype) with (of unknown genotype) with its recessive parent.Significance: is to know the homozygocity or heterozygocity of the unknown hybrid.

GENETIC TERMINOLOGYGENETIC TERMINOLOGYQ. What are F GENERATIONS ?

F- Filial (SON) generation.

F1 -First filial generation obtained by crossing two true obtained by crossing two true breeding varieties.

F2- Second filial generation.

EXAMPLES ON EXAMPLES ON MENDELIAN GENETICS

Q State Mendel’s law of Q State Mendel’s law of Q. State Mendel’s law of Q. State Mendel’s law of segregation. Describe segregation. Describe

h b id ith h b id ith monohybrid cross with a monohybrid cross with a suitable example and derive Fsuitable example and derive F22ratios.ratios.

1st LAW OF MENDEL1 LAW OF MENDEL• Law of Segregation /

Law of purity of gametes.Law of purity of gametes.

• When in a cross, a pair of , pcontrasting genes come together in a hybrid each gene g y gfor a character gets segregated at the time of g ggamete formation.

MONOHYBRID CROSS EXPT.

PG F1 F2

Crossing 2 purelines for height in pea

PG Phenotype homozygous homozygous

Tall DwarfGenotype TT ttGametes T t

F1 Genotype TtF1 Genotype TtPhenotype heterozygous tall

(hybrid)(hybrid)

F1 Phenotype heterozygous tallGenotype TtGenotype Tt

(selfing)Gametes T and tGametes T and t

♂♂♀♀

TT tt

F2

♀♀TT TTTT

h t llh t llTtTt

h t t llh t t llhom tallhom tall het tallhet talltt TtTt tttt

Phenotypic ratio is 3 : 1

het tallhet tall hom dwarfhom dwarf

yGenotypic ratio is 1 : 2 : 1

Q. State Mendel’s law of Q. State Mendel’s law of independent assortment Derive independent assortment Derive independent assortment. Derive independent assortment. Derive PR & GR of FPR & GR of F22 generation when generation when pure & dominant homozygous pure & dominant homozygous pure & dominant homozygous pure & dominant homozygous round and yellow seeded plant round and yellow seeded plant is crossed with a its is crossed with a its homozygous recessive plant.homozygous recessive plant.yg pyg p

2nd Law of Mendel.2 Law of Mendel.• Law of independent assortment• When in a cross, two or more

pairs of contrasting genes are brought together in a hybrid each gene for a character assorts grandomly and independently at the time of gamete formation. g

DIHYBRID CROSS EXPT.DIHYBRID CROSS EXPT.PGPG Phenotype Phenotype homozygoushomozygous homozygoushomozygous

roundround & yellow wrinkled & green& yellow wrinkled & greenseeded plantseeded plant seeded plantseeded plant

GenotypeGenotype RRYYRRYY rryyrryyGenotypeGenotype RRYYRRYY rryyrryyGametesGametes RYRY ryry

FF11 Genotype RrYyGenotype RrYyPh tPh tPhenotypePhenotype heterozygous round & heterozygous round &

yellow seeded plantyellow seeded plant

(hybrid)(hybrid)(hybrid)(hybrid)

FF11 Phenotype heterozygous Phenotype heterozygous round & yellowround & yellowround & yellowround & yellow

Genotype Genotype RrYyRrYy((selfingselfing))

GametesGametes RY RY RyRy rYrY ryry

FF22 Representing the gametes in Representing the gametes in the the PunnetPunnet square shows …..square shows …..qq

♂♂ RYRY RyRy rYrY ryry♂♂♀♀

RYRY RyRy rYrY ryry

RYRY RRYYRRYY RRYRRY R YYR YY R YR YRYRY RRYYRRYY RRYyRRYy RrYYRrYY RrYyRrYy

RyRy RRYyRRYy RRyyRRyy RrYyRrYy RryyRryy

rYrY RrYYRrYY RrYyRrYy rrYYrrYY rrYyrrYy

ryry RrYyRrYy RryyRryy rrYyrrYy rryyrryy

And finally the ratios

• Phenotypic ratio is9 : 3 : 3 : 19 : 3 : 3 : 1

• Genotypic ratio is1 : 2 : 2 : 4 : 1 : 2 : 1 : 2 : 11 : 2 : 2 : 4 : 1 : 2 : 1 : 2 : 1

Q. What is MULTIPLE Q. What is MULTIPLE ALLELISM ?

A character may be A character may be determined by two or more number of alleles called number of alleles called multiple allelism.I th ll li i In the allelic pair, one gene undergoes mutation more than once resulting in many than once resulting in many alternative forms called gene polymorphism.gene polymorphism.

HUMAN BLOOD GROUPS (ABO SYSTEM)(ABO SYSTEM)

-Blood has two components;p ;plasma and cells.

-RBC has agglutinogen (A & B)gg g ( )-Plasma has agglutinin

(anti-a & anti-b)( )-Antigen-antibody reaction in any

blood group helps in immunological g p p gresponse.

HUMAN BLOOD GROUPING (ABO SYSTEM)(ABO SYSTEM)

Blood Blood Blood Blood grougroupp

antigenantigen antibodyantibodypp

AA AA antianti--bbBB BB antianti--aa

ABAB A & BA & BABAB A & BA & B --------------

OO antianti--a a OO -------------- &anti&anti--bb

Q. Name the gene responsible for blood

groups in man ?g p

Burnstein – the gene I h l ti (I) l t d Isohaemoagglutinogen (I) located on 9th autosomal chromosomei ibl f ti is responsible for antigen property of any blood group.

Q. What are the possible genotypes present in human

blood group system ?g p y

Blood Blood Possible Possible ditiditigroupgroup genotypesgenotypes conditioncondition

AA IIAAIIAA IIAAIIOO Homo & heteroHomo & heteroAA II II ,I,I II Homo & heteroHomo & hetero

BB IIBBIIBB,I,IBBIIOO Homo & heteroHomo & hetero

ABAB IIAAIIBB codominancecodominance

OO IIOOIIOOOO IIOOIIOO homozygoushomozygous

Inheritance based questions.

Q. What are the possible blood groups in the offsprings when

the parents have the blood pgroups A and B ?

Inheritance.

♂ ♀blood group A blood group B

Genotypes IAIO IBIO Genotypes I I I I

Gametes IA IO IB IO

Blood gr. in their childrenshow

AB A B O AB A B O

Inheritance of Rh factore ta ce o acto

1. another antigen on RBC,2. compatibility test in blood

transfusion,3. Rh incompatible marriages,HDN (Erythroblastosis foetalis)

Sex-linked inheritance

S ti h t Somatic character genes are linked with allosomes.

X-linked character-colourbli d h hili tblindness, haemophilia etc.

Y li k d h tY-linked characters-hypertrichosis, ichthyosis.

4 Se4 Se Linked TraitsLinked Traits4 Sex4 Sex--Linked Traits:Linked Traits:

1. Normal Color Vision:1. Normal Color Vision:A: 29,A: 29, B: 45,B: 45, C: C: ----, D: 26, D: 26

2 R d2 R d G CBli dG CBli d2. Red2. Red--Green CBlind:Green CBlind:A: 70,A: 70, B: B: ----,, C: 5,C: 5, D: D: ----

3. Red Color3. Red Color--blind:blind:A: 70,A: 70, B: B: ----,, C: 5,C: 5, D: 6D: 6

4. Green Color4. Green Color--Blind:Blind:A: 70,A: 70, B: B: ----,, C: 5,C: 5, D: 2D: 2

This is how the colour blind persons see the traffic signal.

Q. What is criss-cross i h it ?inheritance ?Explain it with

f t i h it reference to inheritance pattern of colourblindness in man.

• To work on tabletTo work on tablet

Genetic disorders.

Chromosomal disorders.Chromosomal disorders.

Q. Briefly explain M li /D ’ Mongolism/Down’s syndrome.y

1. Dr. J.L Down discovereddiscovered.

2. Attributed to mother of 40 i i bi th40+ age giving birth,

3. Autosomal trisomy,4. Chromosomal complement

45A+XY=47.55. due to non-disjunction

of chromosomeof chromosome.

Symptoms:- short stature- short stature,- wide gaped open mouth,- mental retardation- mental retardation,- low intelligence quotient,- sensitive to injection- sensitive to injection,- a distinct fold in the palm,- epinasty- epinasty,- webbed neck with

short limbsshort limbs,- congenital heart defects, etc.

Similar questions may be asked related to other chromosomal

disorders, such as

Cri-du-chat syndrome,44A+XY=4644A+XY=46

Klinefelter’s syndrome,44A+XXY=4744A+XXY=47

Turner’s syndrome.44A+XO=45

Similarly there are manygene disorders (faulty genes)

identified in man.

They are;Haemophilia, p ,Sickle-celled-anaemia, phenylketonuria, phenylketonuria, cystic fibrosis, etc.

Q. What is SCA ? How is it caused ?A t l di d h An autosomal gene disorder where

RBCs become sickle shaped.Hb i l th i i HbA is a normal gene synthesizing normal haemoglobin but SCA have

f lt Hbfaulty gene HbS.HbS synthesizes abnormal haemoglobin

h 6th i id l i l d where 6th aminoacid gla is replaced with val causing sickling of RBCs causing blockage and even death.

PART – IIBiodiversity topicsBiodiversity topics

Q What is BIODIVERSITY ?Q. What is BIODIVERSITY ?

It is the totality of all It is the totality of all living organisms

inhabiting the biosphereinhabiting the biosphere.

Q. What is species diverstity ?• It refers to the variety of

species within the biosphere.p pSpecies diversity consists of two

components, species richnesscomponents, species richnessand species evenness. Species richness is a simple count of richness is a simple count of species, whereas species evenness quantifies how equal evenness quantifies how equal the abundances of the species are. are.

Q Wh t d d Q Wh t d d Q. What are endangered Q. What are endangered species ? Give one example.species ? Give one example.

A species which is likely to become extinct due to the become extinct due to the loss of its natural habitats.

Ex. Flying squirrel, Indian rhino, Lion tailed macaque,….Lion tailed macaque,….

IUCN status categories in RDB (R d D t B k)RDB (Red Data Book)

• Endemic speciesp• Endangered species ( EN )• Critically endangered ( CE )y g ( )• Near threatened ( NT )• Threatened species ( T )• Vulnerable species ( V )• Rare species ( R )• Data deficient ( DD )• Least concerned ( LC )

Q. What are sacred groves ?Gi lGive example.

• Sacred groves are the Sacred groves are the traditionally conserved forests dedicated to the local deity.y

• Ex Mawsmai at Cherrapunji • Ex. Mawsmai at Cherrapunji, Deodar in Shimla, Devarabana, Hulidevana kadu etc.Hulidevana kadu etc.

Q. What are sacred species ?Gi lGive example.

• Species of cultural values h t i l t d where certain plants and

animals are protected t diti ll d ti traditionally and continue to be conserved by man. A i t th l i t Ancient mythology associates sacred species to Gods so th t h ththat no one harms them.

Ex. Tulsi, Banyan tree, Cobra, Cow etc.

Q. What are biodiversity ‘hotspots’ ?Mention any two ‘hotspots’ in India. Mention any two hotspots in India.

““Hotspots are Earth’s Biologically Hotspots are Earth’s Biologically Hotspots are Earth’s Biologically Hotspots are Earth’s Biologically Richest and Most Endangered Richest and Most Endangered T t i l E iT t i l E i ””Terrestrial EcoregionsTerrestrial Ecoregions”. ”.

Western ghats and east himalayasWestern ghats and east himalayas

Q. What is biodiversity depletion ?. Q. What is biodiversity depletion ?. Explain any four anthropocentric

causes of bio-depletion.causes of bio-depletion.

• Loss of life forms is biodiversity depletiondepletion.It is caused by either natural calamities such as earthquake, q ,volcanoes, tsunami, el nino, floods, forest fire etc. or by human interference.human interference.

…

Anthropocentric causes

• Urbanisation: encroaching natural habitat for infrastructure natural habitat for infrastructure making.

• Expansion of agriculture: Expansion of agriculture: intensive conversion into monoculture crop lands.

• Deforestation: depleted forested area.P ll ti d i bl h i • Pollution: undesirable change in the environment.

Anthropocentric causes …• Acidification of soil and water: • Acidification of soil and water:

by acid rain and toxic effluent dumpdump.

• Mining activities: for extraction of oresof ores.

• Desertification: conversion of productive land into barrenproductive land into barren.

• Loss of soil fertility: removal of rich nutrients from the top soilrich nutrients from the top soil.

Q. What is TEK ? Explain different Q. What is TEK ? Explain different methods of conservation of soil.

T diti l E l i l T diti l E l i l Traditional Ecological Traditional Ecological Knowledge is the first hand Knowledge is the first hand knowledge about the knowledge about the ecosystems existing with the ecosystems existing with the ecosystems existing with the ecosystems existing with the traditional communities of men traditional communities of men who live in therewho live in therewho live in there.who live in there.

Conservation of soil Conservation of soil

• Aims at prevention of soil Aims at prevention of soil erosion and maintenance of soil fertility.y

1. Afforestation

2. Restricted grazing2. Restricted grazing

3. Crop rotation

4 Mulching4 Mulching4. Mulching4. Mulching

5 Humus application5 Humus application5. Humus application5. Humus application

6. Contour farming6. Contour farminggg

7. Terracing7. Terracing

8. Strip cropping.8. Strip cropping.

& WE ALL WISH YOU& WE ALL WISH YOU