biology-class-12-unit-06-chapter-06-genetics-evolution-principles-of-inheritance-variation-l-6-7-23inkiossh8

### <Success style="font-size:25px"> Genetics Evolution Principles Of Inheritance Variation L-6 </Success>
### <primary style="font-size:24px"> Haemophilia </primary>
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- Bleeders disease
- Caused by recessive gene seen in the X chromosome
- Blood of the patient lacks anti haemophilic globulin
- Causes profussive bleeding
- Reported first in Queen Victoria
- Carriers transmit this disease to son

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<footer style = "font-size: 18px"> $\rightarrow$ Genetics and evolution $\rightarrow$ <span style = "color:blue"> Haemophilia </span> $\rightarrow$ X - linked inheritence $\rightarrow$ X - linked inheritence </footer>

### <Success style="font-size:25px"> Genetics Evolution Principles Of Inheritance Variation L-6 </Success>
### <primary style="font-size:24px"> Colour blindness in man </primary>
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- Red green colour blindness is an example of sex linked inheritance. It is due to a recessive mutation of a normal dominant gene for colour vision

- Inability to distinguish red from green colour due to lack of one of the primary con pigment in the retina

- Males are usually more affected due to hemizygous
- condition

- It is due a recessive gene linked to the X chromosome

- Females are affected only when both the X chromosomes have the recessive mutant allele

- Heterozygotes are carriers. It shows criss-cross pattern of inheritance

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<footer style = "font-size: 18px">X - linked inheritence $\rightarrow$ X - linked inheritence $\rightarrow$ <span style = "color:blue"> Colour blindness in man </span> $\rightarrow$ Colour blindness in man $\rightarrow$ Sickle cell anaemia (Autosomal disorder) </footer>

### <Success style="font-size:25px"> Genetics Evolution Principles Of Inheritance Variation L-6 </Success>
### <primary style="font-size:24px"> Sickle cell anaemia (Autosomal disorder) </primary>
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- Auto some linked recessive trait
- Transmitted when both the parents are carriers of the gene
- Controlled by a single pair of alleles- HbA and Hbs
- Homozygous individuals are affected Hbs Hbs
- It can be seen both in males and females
- Heterozygotes are carriers

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<footer style = "font-size: 18px">Colour blindness in man $\rightarrow$ Colour blindness in man $\rightarrow$ <span style = "color:blue"> Sickle cell anaemia (Autosomal disorder) </span> $\rightarrow$ Cause for sickle cell anaemia $\rightarrow$ Sickle cell anaemia </footer>

### <Success style="font-size:25px"> Genetics Evolution Principles Of Inheritance Variation L-6 </Success>
### <primary style="font-size:24px"> Cause for sickle cell anaemia </primary>
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<footer style = "font-size: 18px">Colour blindness in man $\rightarrow$ Sickle cell anaemia (Autosomal disorder) $\rightarrow$ <span style = "color:blue"> Cause for sickle cell anaemia </span> $\rightarrow$ Sickle cell anaemia $\rightarrow$ Sickle cell anaemia </footer>

### <Success style="font-size:25px"> Genetics Evolution Principles Of Inheritance Variation L-6 </Success>
### <primary style="font-size:24px"> Sickle cell anaemia </primary>
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- Glutamic acid is replaced by valine amino acid in the affected individual
- It is in the sixth position of beta globin chain of the haemoglobin molecule
- In the sixth codon in the beta globin gene there is a single base substitution from GAG to GUG
- The mutant haemoglobin molecule undergoes polymerisation under low oxygen tension and changes to sickle shaped

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<footer style = "font-size: 18px">Cause for sickle cell anaemia $\rightarrow$ Sickle cell anaemia $\rightarrow$ <span style = "color:blue"> Sickle cell anaemia </span> $\rightarrow$ Advantage of sickle celled anaemia $\rightarrow$ Phenylketonuria </footer>

### <Success style="font-size:25px"> Genetics Evolution Principles Of Inheritance Variation L-6 </Success>
### <primary style="font-size:24px"> Advantage of sickle celled anaemia </primary>
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- Heterozygotes (carriers) of sickle cell anaemia have some selective advantage

- It lowers the chance of developing malaria.

- Since the RBCs have abnormal haemoglobin, they become sickle shaped more readily when they are infected - - with malarial parasites, and the parasites will die inside the sickle shaped cells. Remaining parasites are destroyed by body's defence mechanism before malaria develops.
- The heterozygous sickle celled anaemic individuals protect the person from malaria.

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<footer style = "font-size: 18px">Sickle cell anaemia $\rightarrow$ Sickle cell anaemia $\rightarrow$ <span style = "color:blue"> Advantage of sickle celled anaemia </span> $\rightarrow$ Phenylketonuria $\rightarrow$ Chromosomal disorders </footer>

### <Success style="font-size:25px"> Genetics Evolution Principles Of Inheritance Variation L-6 </Success>
### <primary style="font-size:24px"> Phenylketonuria </primary>
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- Inborn error in metabolism
- Caused due to autosomal recessive gene
- Lacks the enzyme (phenylalanine hydroxyalase) that converts phenylalanine to tyrosine
- So phenylalanine get accumulated in the blood and converted into phenyl pyruvic acid and other derivatives
- Accumulation of these in the brain causes mental retardation
- It is excreted through the kidney
- Urine turns into black when exposed to air
- So known as black urine disease

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<footer style = "font-size: 18px">Sickle cell anaemia $\rightarrow$ Advantage of sickle celled anaemia $\rightarrow$ <span style = "color:blue"> Phenylketonuria </span> $\rightarrow$ Chromosomal disorders $\rightarrow$ Down's syndrome (Autosomal disorder) </footer>

### <Success style="font-size:25px"> Genetics Evolution Principles Of Inheritance Variation L-6 </Success>
### <primary style="font-size:24px"> Chromosomal disorders </primary>
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- Caused due to addition or deletion of chromosomes
- Ploidy- Refers to the number of sets of chromosomes
- Polyploidy Addition of many sets of chromosomes
- Aneuploidy-- Addition or deletion of a single chromosome from the normal diploid set

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<footer style = "font-size: 18px">Advantage of sickle celled anaemia $\rightarrow$ Phenylketonuria $\rightarrow$ <span style = "color:blue"> Chromosomal disorders </span> $\rightarrow$ Down's syndrome (Autosomal disorder) $\rightarrow$ Down's syndrome (Autosomal disorder) </footer>

### <Success style="font-size:25px"> Genetics Evolution Principles Of Inheritance Variation L-6 </Success>
### <primary style="font-size:24px"> Down's syndrome (Autosomal disorder) </primary>
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- It is also known as Mongolism
- Women above the age of 40 are likely to produce such children
- It is due to non-disjunction of homologous chromosomes (21st chromosome)
- A few victims live up to maturity and produce Mongolian and normal children at equal proportion
- Individuals having Down's syndrome are likely to develop leukaemia and Alzheimer's disease

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<footer style = "font-size: 18px">Chromosomal disorders $\rightarrow$ Down's syndrome (Autosomal disorder) $\rightarrow$ <span style = "color:blue"> Down's syndrome (Autosomal disorder) </span> $\rightarrow$ Down's syndrome (Autosomal disorder) $\rightarrow$ Symptoms </footer>

### <Success style="font-size:25px"> Genetics Evolution Principles Of Inheritance Variation L-6 </Success>
### <primary style="font-size:24px"> Symptoms </primary>
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- Short neck
- Stubby fingers
- Underdeveloped gonads and genetalia
- A Mongolian type of eye lid fold
- Flat nose
- Permanently open mouth
- Projecting lower lip
- Protruding tongue

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<footer style = "font-size: 18px">Down's syndrome (Autosomal disorder) $\rightarrow$ Symptoms $\rightarrow$ <span style = "color:blue"> Symptoms </span> $\rightarrow$ Klinefelter's Syndrome $\rightarrow$ Symptoms </footer>

### <Success style="font-size:25px"> Genetics Evolution Principles Of Inheritance Variation L-6 </Success>
### <primary style="font-size:24px"> Turner's syndrome </primary>
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- Caused due to absence of one X chromosome
- Female showing male characters
- 2n = 45, XO
- Sexually sterile
- Rudimentary ovaries
- Short stature
- webbed neck, broad chest
- It is due to the production of an abnormal egg with autosomes only when fuses X type sperm or normal egg with abnormal sperm with autosome only

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<footer style = "font-size: 18px">Klinefelter's Syndrome $\rightarrow$ Symptoms $\rightarrow$ <span style = "color:blue"> Turner's syndrome </span> $\rightarrow$ Karyotype $\rightarrow$ Thank you </footer>