Question

Inheritance of haemophilia in human beings​

Answer 1

Answer:

haemophiliA and haemophilia B are inherited in an excellent recessive pattern the genes associated with this condition are located on the X chromosome

Answer 2

$\large\underline{\boxed{\purple{\sf \orange{\maltese}\: Inheritance\: of \ Haemophilia \ in \ Human }}}$

Haemophilia haemophilia is a defect of blood which prevents its clotting.Haemophilic persons bleed excessively when injured . It is caused by a reccesive gene (h) located in the X chromosome.

This recessive gene loses its ability to produce the coagulent.

$\underline{\underline{\pink{\bf Inheritance :- }}}$

Man has one X chromosome and one Y chromosome . The gene for haemophilia is located in the X chromosome is able to produce the defect because there is no homologue of this gene in the Y chromosome to check its expression.

Woman has two X chromosomes . For her to be haemophilic , it is necessary for both the X chromosomes' gene to be haemophilic. Such feamales are not born as the combination of two reccesive gene is fatal.

If only one X chromosome bears a gene for haemophilia , its dominant homologous gene in the other X chromosome will check the expression of the reccesive gene. Such females are carriers.

The three cases are discussed in the attachment :-

$\rule{200}2$

$\underline{\underline{\pink{\bf Some \ more \ Information :- }}}$

➳ $\underline{\green{\sf Homologous \: Chromosomes : }}$

• These are chromosome pairs of approximately same length, centromere position and staining pattern, with genes for the same characteristics at the corresponding loci

• In an organism, one homologous chromosome is inherited from mother and other from the father .

➳ $\underline{\green{\sf Some \ hereditary \ characters \ in \ Humans : }}$

$\boxed{\begin{array}{r|r|r|r} \underline{\red{ \sf S . No.}} & \underline{\red{ \sf Character}} & \underline{\red{ \sf Dominant \ Allele}} & \underline{\red{ \sf Recessive \ Allele }} \\ \sf 1 & \sf Hair & \sf Curly & \sf Straight \\ \sf 2 & \sf Skin \ color & \sf Normal & \sf Albino \\ \sf 3 & \sf Ear\ Lobes & \sf Free & \sf Attached \\ \sf 4& \sf Eyes & \sf Brown/ Black & \sf Blue \\ \sf 5 & \sf Tongue\ Rolling & \sf Ability \ to \ roll & \sf Inability \ to \ roll \\\end{array}}$