Two autosomal genetic disorders are as follows. 1. Sickle cell Anaemia It is an autosomal linked recessive disorder, which is caused by point mutation in the beta-globin chain of haemoglobin pigment of the blood. The disease is characterized by sickle shaped red blood cells, which are formed due toRead more
Two autosomal genetic disorders are as follows.
1. Sickle cell Anaemia
It is an autosomal linked recessive disorder, which is caused by point mutation in the beta-globin chain of haemoglobin pigment of the blood. The disease is characterized by sickle shaped red blood cells, which are formed due to the mutant haemoglobin molecule. The disease is controlled by HbA and HbS allele. The homozygous individuals with genotype, HbS HbS, show the symptoms of this disease while the heterozygous individuals with genotype, HbA HbS, are not affected. However, they act as carriers of the disease.
Symptoms
Rapid heart rate, breathlessness, delayed growth and puberty, jaundice, weakness, fever, excessive thirst, chest pain, and decreased fertility are the major symptoms of sickle cell anaemia disease.
2. Down’s syndrome
It is an autosomal disorder that is caused by the trisomy of chromosome 21.
Symptoms
The individual is short statured with round head, open mouth, protruding tongue, short neck, slanting eyes, and broad short hands. The individual also shows retarded mental and physical growth.
Sutton and Boveri proposed the chromosomal theory of inheritance in 1902. They linked the inheritance of traits to the chromosomes. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-5/
Sutton and Boveri proposed the chromosomal theory of inheritance in 1902. They linked the inheritance of traits to the chromosomes.
Point mutation is a change in a single base pair of DNA by substitution, deletion, or insertion of a single nitrogenous base. An example of point mutation is sickle cell anaemia. It involves mutation in a single base pair in the beta-globin chain of haemoglobin pigment of the blood. Glutamic acid inRead more
Point mutation is a change in a single base pair of DNA by substitution, deletion, or insertion of a single nitrogenous base. An example of point mutation is sickle cell anaemia. It involves mutation in a single base pair in the beta-globin chain of haemoglobin pigment of the blood. Glutamic acid in short arm of chromosome II gets replaced with valine at the sixth position.
(a) Co-dominance:- Co-dominance is the phenomenon in which both the alleles of a contrasting character are expressed in heterozygous condition. Both the alleles of a gene are equally dominant. ABO blood group in human beings is an example of co-dominance. The blood group character is controlled by tRead more
(a) Co-dominance:- Co-dominance is the phenomenon in which both the alleles of a contrasting character are expressed in heterozygous condition. Both the alleles of a gene are equally dominant. ABO blood group in human beings is an example of
co-dominance. The blood group character is controlled by three sets of alleles, namely, Iᴬ, Iᴮ, and i. The alleles, Iᴬ and Iᴮ, are equally dominant and are said to be co-dominant as they are expressed in AB blood group. Both these alleles do not interfere with the expression of each other and produce their respective antigens. Hence, AB blood group is an example of co-dominance.
(b) Incomplete dominance:- Incomplete dominance is a phenomenon in which one allele shows incomplete dominance over the other member of the allelic pair for a character. For example, a monohybrid cross between the plants having red flowers and white flowers in Antirrhinum species will result in all pink flower plants in F1 generation. The progeny obtained in F1 generation does not resemble either of the parents and exhibits intermediate characteristics. This is because the dominant allele, R, is partially dominant over the other allele, r. Therefore, the recessive allele, r, also gets expressed in the F1 generation resulting in the production of intermediate pink flowering progenies with Rr genotype.
The blood group characteristic in humans is controlled by three set of alleles, namely, Iᴮ, Iᴬ, and i. The alleles, IA and IB, are equally dominant whereas allele, i, is recessive to the other alleles. The individuals with genotype, Iᴬ Iᴬ and Iᴬ i, have blood group A whereas the individuals with genRead more
The blood group characteristic in humans is controlled by three set of alleles, namely, Iᴮ, Iᴬ, and i. The alleles, IA and IB, are equally dominant whereas allele, i, is recessive to the other alleles. The individuals with genotype, Iᴬ Iᴬ and Iᴬ i, have blood group A whereas the individuals with genotype, Iᴮ Iᴮ and Iᴮ i, have blood group B. The persons with genotype IA IB have blood group AB while those with blood group O have genotype ii.
Hence, if the father has blood group A and mother has blood group B, then the possible genotype of the parents will be
Father Mother
Iᴬ Iᴬ or Iᴬ i Iᴮ Iᴮ or Iᴮ i
A cross between homozygous parents will produce progeny with AB blood group.
A cross between heterozygous parents will produce progenies with AB blood group (IᴬIᴮ) and O blood group (ii).
Mention any two autosomal genetic disorders with their symptoms.
Two autosomal genetic disorders are as follows. 1. Sickle cell Anaemia It is an autosomal linked recessive disorder, which is caused by point mutation in the beta-globin chain of haemoglobin pigment of the blood. The disease is characterized by sickle shaped red blood cells, which are formed due toRead more
Two autosomal genetic disorders are as follows.
1. Sickle cell Anaemia
It is an autosomal linked recessive disorder, which is caused by point mutation in the beta-globin chain of haemoglobin pigment of the blood. The disease is characterized by sickle shaped red blood cells, which are formed due to the mutant haemoglobin molecule. The disease is controlled by HbA and HbS allele. The homozygous individuals with genotype, HbS HbS, show the symptoms of this disease while the heterozygous individuals with genotype, HbA HbS, are not affected. However, they act as carriers of the disease.
Symptoms
Rapid heart rate, breathlessness, delayed growth and puberty, jaundice, weakness, fever, excessive thirst, chest pain, and decreased fertility are the major symptoms of sickle cell anaemia disease.
2. Down’s syndrome
It is an autosomal disorder that is caused by the trisomy of chromosome 21.
Symptoms
The individual is short statured with round head, open mouth, protruding tongue, short neck, slanting eyes, and broad short hands. The individual also shows retarded mental and physical growth.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-5/
Who had proposed the chromosomal theory of inheritance?
Sutton and Boveri proposed the chromosomal theory of inheritance in 1902. They linked the inheritance of traits to the chromosomes. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-5/
Sutton and Boveri proposed the chromosomal theory of inheritance in 1902. They linked the inheritance of traits to the chromosomes.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-5/
What is point mutation? Give one example.
Point mutation is a change in a single base pair of DNA by substitution, deletion, or insertion of a single nitrogenous base. An example of point mutation is sickle cell anaemia. It involves mutation in a single base pair in the beta-globin chain of haemoglobin pigment of the blood. Glutamic acid inRead more
Point mutation is a change in a single base pair of DNA by substitution, deletion, or insertion of a single nitrogenous base. An example of point mutation is sickle cell anaemia. It involves mutation in a single base pair in the beta-globin chain of haemoglobin pigment of the blood. Glutamic acid in short arm of chromosome II gets replaced with valine at the sixth position.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-5/
Explain the following terms with example:-(a) Co-dominance (b) Incomplete dominance
(a) Co-dominance:- Co-dominance is the phenomenon in which both the alleles of a contrasting character are expressed in heterozygous condition. Both the alleles of a gene are equally dominant. ABO blood group in human beings is an example of co-dominance. The blood group character is controlled by tRead more
(a) Co-dominance:- Co-dominance is the phenomenon in which both the alleles of a contrasting character are expressed in heterozygous condition. Both the alleles of a gene are equally dominant. ABO blood group in human beings is an example of
co-dominance. The blood group character is controlled by three sets of alleles, namely, Iᴬ, Iᴮ, and i. The alleles, Iᴬ and Iᴮ, are equally dominant and are said to be co-dominant as they are expressed in AB blood group. Both these alleles do not interfere with the expression of each other and produce their respective antigens. Hence, AB blood group is an example of co-dominance.
(b) Incomplete dominance:- Incomplete dominance is a phenomenon in which one allele shows incomplete dominance over the other member of the allelic pair for a character. For example, a monohybrid cross between the plants having red flowers and white flowers in Antirrhinum species will result in all pink flower plants in F1 generation. The progeny obtained in F1 generation does not resemble either of the parents and exhibits intermediate characteristics. This is because the dominant allele, R, is partially dominant over the other allele, r. Therefore, the recessive allele, r, also gets expressed in the F1 generation resulting in the production of intermediate pink flowering progenies with Rr genotype.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-5/
A child has blood group O. If the father has blood group A and mother blood group B, work out the genotypes of the parents and the possible genotypes of the other offsprings.
The blood group characteristic in humans is controlled by three set of alleles, namely, Iᴮ, Iᴬ, and i. The alleles, IA and IB, are equally dominant whereas allele, i, is recessive to the other alleles. The individuals with genotype, Iᴬ Iᴬ and Iᴬ i, have blood group A whereas the individuals with genRead more
The blood group characteristic in humans is controlled by three set of alleles, namely, Iᴮ, Iᴬ, and i. The alleles, IA and IB, are equally dominant whereas allele, i, is recessive to the other alleles. The individuals with genotype, Iᴬ Iᴬ and Iᴬ i, have blood group A whereas the individuals with genotype, Iᴮ Iᴮ and Iᴮ i, have blood group B. The persons with genotype IA IB have blood group AB while those with blood group O have genotype ii.
Hence, if the father has blood group A and mother has blood group B, then the possible genotype of the parents will be
Father Mother
Iᴬ Iᴬ or Iᴬ i Iᴮ Iᴮ or Iᴮ i
A cross between homozygous parents will produce progeny with AB blood group.
A cross between heterozygous parents will produce progenies with AB blood group (IᴬIᴮ) and O blood group (ii).
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-5/