Question

$XO$ type of sex determination and $XY$ type of sex determination are the examples of

• A. male heterogamety
• B. female heterogamety
• C. male homogamety
• D. both (b) and (c)

Answer 1

Answer: (A)

In $XO$ type and $XY$ type sex determining mechanisms, males produce two different types of gametes, $(a)$ either with or without $X$-chromosome ($XO$ type), $(b)$ some gametes with $X$-chromosome and some with $Y$-chromosome ($XY$ type). Such type of sex determination mechanism is designated to be the example of male heterogamety. In both, females are homogametic and produce $X$ type of gametes in both the cases and have $XX$ genotype.