Explain Medel\'s two law in terms of chromosomal behavior during meiosis? In a p

ID: 74954 • Letter: E

Question

Explain Medel's two law in terms of chromosomal behavior during meiosis? In a pedigree where an autosomal recessive disease appears, an affected parent frequently has unaffected children. But unaffected parents can have affected offspring. Why? Explain Medel's two law in terms of chromosomal behavior during meiosis? In a pedigree where an autosomal recessive disease appears, an affected parent frequently has unaffected children. But unaffected parents can have affected offspring. Why? In a pedigree where an autosomal recessive disease appears, an affected parent frequently has unaffected children. But unaffected parents can have affected offspring. Why?

Explanation / Answer

Mendel’s’ laws:

1.Law of segregation: One of 2 principles of genetic heredity first formulated by Gregor Mendel,elucidated on his genetic experiments with pea plants and finally described that the members of “a pair of homologous chromosomes segregate during meiosis and are distributed to different

gametes” so that the offspring acquires one factor from each parent.

2. Law of independent assortment: Second of these two laws, describing that “each individual member of a pair of homologous chromosomes segregates during meiosis independently of the members of other pairs, and finally result in alleles carried on different chromosomes are distributed randomly to the gametes.

Reasons:

Sex-linked Recessive (X-linked):

Children of an affected male (father) will not be affected. Though, 100% of the female offspring will be carriers of the disease.

An unaffected carrier female (heterozygous mother) will have about 50% affected male offspring and no affected female offspring (even though about 50% of the female offspring will be carriers).

Sex-linked Dominant (X-linked)

Affected male will constantly produce affected female offspring and unaffected male child.

Affected female will produce nearly about 50% affected male and 50% affected female offspring if she is heterozygous. If she is homozygous, 100% of the offspring will be affected.

Sex-linked (Y-chromosome)

Traits particularly are often passed from father to son.

Only male offspring would be affected.