Question

У человека рыжий цвет волос доминирует над русым а веснушки над их отсутствием. гетерозиготный рыжеволосый без веснушек мужчина женился на русоволосой женщине с веснушками .определить в процентах вероятность рождения ребенка рыжеволосого с веснушками

Answer 1

А -- рыжий цвет волос

а -- русый цвет

В -- наличие веснушек

b -- их отсутствие

Женщина может быть гетеро- или гомозиготна по признаку наличия веснушек,поэтому рассмотрим два варианта.

Вариант 1:

P: ♂Aabb x ♀aaBb

G: Ab;ab        aB;ab

F1: AaBb (рыжий с веснушками); Aabb (рыжий без веснушек); aaBb (русый с веснушками); aabb (русый без веснушек).

Вероятность составит 25%.

Вариант 2:

P: ♂Aabb x ♀aaBB

G: Ab;ab        aB

F1: AaBb (рыжий с веснушками); aaBb (русый с веснушками)

В этом случае вероятность составит 50%.

Answer 2

Determining the Probability of a Child Having Red Hair and Freckles

To determine the probability of a child having red hair and freckles, we need to consider the genetic traits of the parents. In this case, we have a heterozygous red-haired man without freckles marrying a red-haired woman with freckles.

The inheritance of hair color and freckles is influenced by multiple genes, but for simplicity, let's assume that these traits are controlled by a single gene each. We'll use the following symbols to represent the genes:

- R: Dominant allele for red hair - r: Recessive allele for non-red hair - F: Dominant allele for freckles - f: Recessive allele for no freckles

Based on the information provided, we can determine the genotypes of the parents:

- The man is heterozygous for red hair and does not have freckles. His genotype is RrFf. - The woman is homozygous for red hair and has freckles. Her genotype is RRFF.

To determine the probability of their child having red hair and freckles, we need to consider the possible combinations of alleles that the child can inherit from each parent.

Possible Allele Combinations for the Child

The man can pass on either the R allele or the r allele for hair color, and the F allele or the f allele for freckles. The woman can only pass on the R allele for hair color and the F allele for freckles.

Therefore, the possible allele combinations for the child are as follows:

1. Child inherits the R allele from the man and the R allele from the woman, and the F allele from the woman: RRFF 2. Child inherits the R allele from the man and the R allele from the woman, and the f allele from the woman: RRFf 3. Child inherits the R allele from the man and the r allele from the woman, and the F allele from the woman: RrFF 4. Child inherits the R allele from the man and the r allele from the woman, and the f allele from the woman: RrFf

Probability Calculation

To calculate the probability of each outcome, we need to consider the chance of each allele being passed on from the parents. Since the man is heterozygous for both traits, there is a 50% chance of passing on either allele. The woman, being homozygous for both traits, will always pass on the dominant alleles.

Therefore, the probability of each outcome is as follows:

1. Probability of child having genotype RRFF: 50% (from the man) * 100% (from the woman) = 50% 2. Probability of child having genotype RRFf: 50% (from the man) * 100% (from the woman) = 50% 3. Probability of child having genotype RrFF: 50% (from the man) * 100% (from the woman) = 50% 4. Probability of child having genotype RrFf: 50% (from the man) * 100% (from the woman) = 50%

Therefore, there is a 50% chance that the child will have red hair and freckles.

Please note that this calculation assumes simple Mendelian inheritance and does not take into account other genetic factors that may influence hair color and freckles.