Which of the following is true about linkage
$I.$ It is phenomenon in which more recombinants are produced in $F_{2}$-generation
$II.$ More parental combination are produced in $F_{2}$-generation
$III.$ Genotype which are present in $F_{1}$ hybrid. Reappear in high frequency in $F_{2}$-generation
$IV.$ It is a phenomenon in which two chromosome are linked
Only $I$
Only $II$
$I$ and $III$
$III$ and $IV$
What is the correct sequence of the following events
$1.$Formation of the chromosome theory of heredity
$2.$Experiments which proved that $DNA$ is the hereditary material
$3.$Mendel's laws of inheritance-discovery
Code :
Select incorrect statement
$(A)$ Linked genes cause absolute lethality
$(B)$ Persons affected by $PKU$ do not show mental disorder
$(C)$ $F_{2}$ ratio in codominance and incomplete dominance are same
$(D)$ Sex of male Drosophila is dependent on $Y-$chromosome
Match the following columns.
Column $- I$ | Column $- II$ |
$(w)$ Blood group | $(a)$ Polygenic inheritance |
$(x)$ Skin colour | $(b)$ Aneuploidy |
$(y)$ Mendelian disorder | $(c)$ Incomplete dominance |
$(z)$ Chromosomal disorder | $(d)$ Sickle-cell anaemia |
$(e)$ Co-dominance |
Which of the following pairs is $wrongly$ matched?
Marriages between close relatives and cousins is not advisable because