Which one of the following conditions in chromosome number is called monosomy?
2n + 1
2n + 2
2n - 1
2n - 2
C.
2n - 1
Monosomy is the condition of having a diploid chromosome complement in which one chromosome lacks its homologous partner. Eg, Turner's Syndrome.
In Turner's Syndrome, there is presence of 45 pair of chromosomes,ie, (2n - 1) XO. It occurs only in females. These females do not mature sexually and are sterile. They have Short stature and normal intelligence.
Tetrasomy or 2n + 2 is a form of aneuploid with the presence of four copies of chromosomes.
Trisomy or 2n + 1 is a chromosomal disorder characterised by an additional chromosome. Eg, Down's syndrome, Patau's syndrome etc.
Nullisomy or 2n-2 is a genetic condition involving the lack of both the normal chromosomal pair for a species.
The map distance between the genes A and B is 3 units, between B and C is 10 units and between C and A is 7 units. The order of the genes in a linkage map constructed on the above data would perhaps be
A, B, C
A, C, B
B, C, A
B, A, C
A person with the sex chromosomes XXY suffers from :
Down's syndrome
Turner's syndrome
Gynandromorphism
Klinefelter's syndrome
Which of the following conditions is related to haemophilia?
A responsible recessive gene present in the X-chromosome
A responsible dominant gene presentin the X-chromosome
A responsible dominant gene present in the Y-chromosome
A responsible dominant gene present in the autosomal chromosome
9: 3: 3: 1 ratio is modified to 9 : 7 ratio due to
complementary gene
epistatic gene
hypostatic gene
supplementary gene
Indicate, the inheritance of which of the following is controlled by multiple alleles?
Colourblindness
Sickle cell anaemia
Blood group
Phenylketoneuria
The absence of which clotting factor leads to haemophilia-A?
Factor VII
Factor VIII
Factor IX
Factor X
One of the following is sex-influenced character
Appearance of beard
Baldness in male
Docile behaviour of female
Low BMR in female