Genetics Answers

Blind girl, parents, brothers and sisters who were also blind, was married to a blind boy, a brother and sister who were also blind, and the other members of the family - mother, father, two sisters and a brother - sighted. From this marriage, 8 sighted children were born. Analyze the pedigree and name the reason for the birth of sighted children in blind parents.

Hypertrichosis is inherited as a trait linked to the Y-chromosome, which manifests itself by 17 years of age. One of the forms of ichthyosis (scaly, patchy thickening of the skin) is inherited as a recessive trait linked to the X chromosome. In a family where the woman is normal, and the husband has only hypertrichosis, a boy was born with signs of ichthyosis.

a) Determine the likelihood of this boy showing hypertrichosis?

b) Determine the probability of birth in this family of children without anomalies and what gender will they be?

Classic hemophilia is transmitted as a recessive trait linked to the X chromosome.

a) A man with hemophilia married a woman who does not have this disease. They give birth to children without anomalies - a daughter and a son, who remarry with non-hemophiliacs. Will grandchildren find hemophilia and what is the likelihood of sickness in the family of a daughter and son?

b) A man with hemophilia marries a normal woman whose father suffered from hemophilia.

Determine the probability of the birth of healthy children in this family

In a family where the parents could hear well and had: one had smooth hair, and the other had curly hair, a deaf child with smooth hair was born. Their second child heard well and had curly hair.

What is the probability of further occurrence of deaf children with curly hair if it is known that the gene for curly hair dominates over smooth hair, deafness is a recessive trait, and both pairs of genes are located on different chromosomes?

Task 1. Describe the crossing schemes and indicate the splitting by genotype and phenotype.

Take, for example, that A is brown eyes and a is blue.

1.1 Splitting by phenotype and genotype when crossing homozygotes by dominant and recessive in the case of complete dominance?

1.2 Splitting by phenotype and genotype when crossing heterozygotes in the case of complete dominance?

1.3 Splitting by phenotype and genotype when crossing heterozygote and homozygote by dominant in case of complete dominance?

1.4 Splitting by phenotype and genotype when crossing heterozygote and homozygote by recessive in case of complete dominance?

in humans, the left chin trait is dominant to the smooth chin trait. a man who is heterozygous for cleft chin and a woman who has smooth chin decide to have chldren. what fraction of their children are predicted to have a smooth chi.

The genes for Tyrosinemia and Marfan syndrome are divided into 4 map units on

chromosome 15. In a couple, the male is heterozygous for these genes inherited from different

parents. The woman is the carrier of the tyrosinemia gene. Tyrosinemia is transmitted in an

autosomal recessive manner, and Marfan syndrome is transmitted in an autosomal dominant

manner. What are the chances of having a healthy child in the family?

The recessive genes for hemophilia A and agamoglobulinemia are 6.4 map units apart

on the X chromosome. What is the probability of having a child with both anomalies in a family

where the father has hemophilia and the mother carries both recessive genes passed on from her

mother?

Mitosis and meiosis are similar processes, but they have some very important differences. Explain how mitosis and meiosis are alike and how they are different. Provide at least two similarities and three differences.

During the cell cycle, when does the chromosomes become visible and invisible ? Also, what does it mean by chromosome 'condense' and what happens if it condenses ?