HETEROGAMETIC SEX

It is also called as Digametic Sex.It refers to the sex of a species in which the ALLOSOMES(sex chromosomes)are not the same.

'''eg: In humans, males are with X and Y sex chromosomes. This condition is HETEROGAMETIC SEX, where as females are with two X sex chromosoms.this condition is'''

HOMOGAMETIC SEX.

'In plants,Malandrum album''also same as Human beings. Males with XY sex chromosomes and females with XX sexchromosome.'''

'''However in birds and reptiles, males have two Z chromosomes. So it is called the HOMOGAMETIC SEX, where as females are wih one Z and one W chromosome. Thus they are heterogametic sex.'''

'''Among insects, females are heterogametic sex. ButDrosophilamale is heterogametic sex.'''

'''This condition is also called as heterogamesis. This can lead to reduced or absent meiotic recombination between the sex chromosomes and in some species this can even extend to autosomes(somatic chromosomes). '''

'''This phenomenon is called ACHIASMY. For example, most lineages of male drosophila are Achismic.Because of lack of recombination on all chromosomes, though females show recombination.'''