How does gain or loss of chromosome(s) takes place in humans? Describe

1.	How does gain or loss of chromosome(s) takes place in humans? Describe one example each of chromosomal disorder along with the symptoms involving an autosome and a sex chromosome.
Answer» Failure of segregation of chromatids during cell division cycle results in the gain or loss of a chromosome(s) ( aneuploidy) Autosomes:- Down’s Syndrome: The cause is the presence of an additional copy of the chromosome number 21 (trisomy of 21) The affected individual is • short statured with small round head, • furrowed tongue and partially open mouth • Palm is broad with characteristic palm crease. • Physical, psychomotor and mental development is retarded Sex chromosomes:- Klinefelter’s Syndrome : This is caused due to the presence of an additional copy of Xchromosome resulting into a karyotype of 47, XXY. Such an individual has overall masculine development • has overall masculine development • feminine development is also expressed by the development of breast/ Gynaecomastia). Such individuals are sterile.

How does gain or loss of chromosome(s) takes place in humans? Describe one example each of chromosomal disorder along with the symptoms involving an autosome and a sex chromosome.

Answer»

Failure of segregation of chromatids during cell division cycle results in the gain or loss of a chromosome(s) ( aneuploidy)

Autosomes:-

Down’s Syndrome: The cause is the presence of an additional copy of the chromosome number 21 (trisomy of 21)

The affected individual is

• short statured with small round head,

• furrowed tongue and partially open mouth

• Palm is broad with characteristic palm crease.

• Physical, psychomotor and mental development is retarded

Sex chromosomes:-

Klinefelter’s Syndrome : This is caused due to the presence of an additional copy of Xchromosome resulting into a karyotype of 47, XXY.

Such an individual has overall masculine development

• has overall masculine development

• feminine development is also expressed by the development of breast/ Gynaecomastia). Such individuals are sterile.