Advertisements
Advertisements
Question
In humans, males are heterogametic and females are homogametic. Explain. Are there any examples where males are homogametic and females heterogametic?
Advertisements
Solution
The term homogametic and heterogametic refer to the organism depending upon whether all the gametes contain one type of sex chromosome (Homo = same) or two different types of sex chromosomes (Hetero = different) Humans show XX/XY type of sex determination i.e. Females contain 2 copies of X chromosome and males contain 1 X and 1 Y chromosome. Therefore, ova produced by females contain the same sex chromosome i.e. X. On the other hand, the sperms contain 2 different types of chromosomes i.e. 50% sperms have X and 50% have Y chromosome open from half the autosomes (Meiosis) Therefore, the sperms are different with respect to the composition of sex chromosome. In case of humans, females are considered to be homogametic while males are heterogametic. Yes, there are examples where males are homogametic and females are heterogametic. In some birds, the mode of sex determination is denoted by ZZ (males) and ZW (females).
APPEARS IN
RELATED QUESTIONS
If X chromosome is inherited from mother and Y from father, the offspring will be male.
Differentiate between ‘ZZ’ and ‘XY’ type of sex-determination mechanisms.
Which of the following is an example of ZW – ZZ type of mechanism of sex determination?
Explain the mechanism of 'sex determination' in birds. How does it differ from that of human beings?
The exchange of genetic material takes place in :
(a) vegetative reproduction
(b) asexual reproduction
(c) sexual reproduction
(d) budding
In human males all the chromosomes are paired perfectly except one. This/these unpaired chromosomes is/are :
(i) large chromosome
(ii) small chromosome
(iii) Y chromosome
(iv) X chromosome
E is the gene for brown eye colour and an is the gene for blue eye colour. which gene is (1) recessive, and (2) dominant?
Both father and mother have the genes Ee in their cells. What colour are their eyes?
Name two animals which have nineteen pairs of chromosomes.
Choose the correct answer :
Human sex chromosomes are __________
Choose the correct answer:
Males have more chances of suffering from sex-linked disease because of ___________
Drone of the honeybees shows haploid number of chromosomes. Illustrate.
Complete the following sentence with appropriate word:
___________ chromosomes do not take part in sex determination.
What is parthenogenesis?
XO type of sex determination and XY type of sex determination are examples of ____________.
Differentiate Intersexes from Supersexes.
Brief about female heterogamety.
Identify the female heterogamety from the chromosomal complements given below.
There are five daughters and no son in a family. It is because
Identify the organism in which ZZ-ZW type of sex determination is observed.
Chromosomal constitution of normal human females can be written as ______.
ZZ/ZW type of sex determination is seen in ______.
In XO type of sex determination ______.
Which of the following combination of chromosome numbers represents the correct sex determination pattern in honey bees?
A man with blood group A marries a woman having blood group O. What will be the blood group of the child?
The maleness of a child is determined by ______
A zygote which has an X-chromosome inherited from the father will develop into a
A trait in an organism is influenced by
Twins are born to a family that lives next door to you. The twins are a boy and a girl. Which of the following must be true?
