Principles Of Inheritance And Variation! Try Out The Quiz

ABO blood group in humans is determined by multiple alleles. This means that there are more than two possible forms of the gene that controls the ABO blood group. These alleles are responsible for the different blood types, such as A, B, AB, and O. Each individual inherits two alleles, one from each parent, which determines their blood type. The presence or absence of certain antigens on the surface of red blood cells is determined by the combination of these alleles. Therefore, the correct answer is multiple alleles.

In hemophilia patients, blood clotting is delayed due to the lack of certain clotting factors. Hemophilia is a genetic disorder that affects the blood's ability to clot properly. Clotting factors are proteins in the blood that help control bleeding by forming clots. Without these clotting factors, the blood is unable to clot efficiently, leading to prolonged bleeding and delayed clotting. This can result in excessive bleeding even from minor injuries or spontaneous bleeding without any apparent cause.

Emasculation is the process of removing stamens from a flower during hybridization. This is done to prevent self-pollination and ensure controlled cross-pollination between desired plants. By removing the stamens, the flower's pollen is eliminated, making it unable to fertilize itself. This allows for the controlled transfer of pollen from the desired male parent to the female parent, resulting in the desired traits being passed on to the offspring. Emasculation is an important step in hybridization to achieve desired genetic combinations and create new varieties of plants.

The explanation for the correct answer, Law of segregation, is that it states that during the formation of gametes, the factors (alleles) for a particular trait separate or segregate equally into different gametes. This means that each gamete will receive only one allele for each trait, without any contamination from other alleles. This principle was proposed by Gregor Mendel and is one of the fundamental laws of inheritance. It explains how traits are inherited from parents to offspring and how genetic variation is maintained in populations.

Klinefelter's syndrome is a genetic disorder that occurs in males due to the presence of an extra X chromosome. The normal male karyotype is 44 + XY, while individuals with Klinefelter's syndrome have an additional X chromosome, resulting in a karyotype of 44 + XXY. This extra chromosome can lead to various physical and developmental abnormalities, including reduced fertility, tall stature, and increased risk of certain medical conditions.

Trisomy refers to a condition where there is an extra copy of a chromosome in an individual's cells. The correct answer, 2n + 1, indicates that the chromosome complement in trisomy is one extra chromosome compared to the normal diploid number (2n). This extra chromosome results in genetic abnormalities and can lead to various disorders, such as Down syndrome (trisomy 21).

In Mirabilis jalapa, the genes for flower color show incomplete dominance. This means that when a red flowered plant is crossed with a white flowered plant, the offspring in the F1 generation will have a phenotype that is intermediate between red and white, resulting in pink flowers. When these pink flowered plants are self-pollinated in the F2 generation, the phenotypic ratio is expected to be 1 red : 2 pink : 1 white. This is because the pink flowered plants in the F1 generation carry both the red and white alleles, and when they undergo segregation in the F2 generation, they can produce offspring with either red, pink, or white flowers. Therefore, the correct answer is 1 : 2 : 1.

Polygenic inheritance refers to the inheritance of traits that are controlled by multiple genes. In the case of skin color in humans, it is influenced by the combined effects of multiple genes. Each gene contributes a small amount to the overall variation in skin color, and the interaction between these genes determines the final phenotype. This type of inheritance does not follow the simple patterns of Mendelian inheritance or involve complementary genes. Instead, it involves the cumulative effects of multiple genes working together to produce a continuous range of phenotypes.

Down's syndrome is a genetic disorder caused by the presence of an extra copy of chromosome 21. Nondisjunction of chromosomes occurs when the chromosomes fail to separate properly during cell division, leading to an abnormal distribution of chromosomes in the resulting cells. In the case of Down's syndrome, nondisjunction of chromosome 21 during either egg or sperm formation results in an extra copy of this chromosome in the fertilized egg. This extra genetic material leads to the physical and cognitive characteristics associated with Down's syndrome.

If the father's blood group is A and the mother's blood group is O, the child cannot have blood groups B or AB. This is because the child can only inherit blood types from their parents, and neither parent has the B antigen. Therefore, the child cannot have blood group B. Additionally, since the mother's blood group is O, which does not have the A or B antigens, the child cannot have blood group AB.

The correct answer suggests that one parent has the genotype IA i (heterozygous for blood type A) and the other parent has the genotype IB i (heterozygous for blood type B). This would explain how the children have blood groups A, AB, and B, as they would inherit one allele from each parent. The IA i parent would pass on the IA allele to the child with blood type A, the IB i parent would pass on the IB allele to the child with blood type B, and both parents would pass on their i allele to the child with blood type AB.

Hypertrichosis of ears is associated with the Y chromosome. Hypertrichosis refers to excessive hair growth, and in this case, it specifically affects the ears. Since the Y chromosome is responsible for determining male sex characteristics, including hair growth patterns, hypertrichosis of ears can be linked to the presence of the Y chromosome. Haemophilia, colour blindness, and night blindness, on the other hand, are not specifically associated with the Y chromosome.

The given cross YyRr x yyrr represents a dihybrid test cross because it involves two different genes (Yy and Rr) and their respective alleles are being crossed with their recessive counterparts (yy and rr). This cross allows for the determination of the genotype of the parent with the unknown genotype. By observing the phenotypic ratios of the offspring, one can deduce the genotype of the parent.

Epicanthus is a symptom of Down's syndrome. Down's syndrome, also known as Trisomy 21, is a genetic disorder caused by the presence of an extra copy of chromosome 21. Epicanthus refers to the presence of a fold of skin that covers the inner corner of the eye, giving the appearance of slanted eyes. This physical characteristic is commonly seen in individuals with Down's syndrome.

If all the sons of a couple are color blind, it indicates that the mother is carrying the color blindness gene. Since color blindness is a recessive trait that is passed on through the X chromosome, it means that the mother must have at least one X chromosome with the color blindness gene. Therefore, the correct answer is that the mother is color blind.