To answer the question The gene for brown eyes is considered dominant. Does he always win if the other parent's eyes are not brown? given by the author old-timer the best answer is 3:1, unless I forgot the arithmetic. That is, such parents will have three children with brown eyes, and the fourth with blue eyes. But if the brown-eyed person himself has grandparents with different eye colors, the likelihood that the child will be blue-eyed increases MAYBE....

Answer from Alina[guru]
No not always. Mom's eyes are brown, father's are blue. I have brown ones, my sister has blue ones, and my second sister has green ones. My son's father has brown eyes, that is, both parents have brown eyes, but his son's eye color is green.

Answer from Neurosis[guru]
no, in my opinion this is nonsense... if he doesn’t always win, why is he dominant?

Answer from Accomplice[newbie]
No, no and NO! My mom and dad are brown-eyed, and I have blue eyes! My husband has brown ones, and our children have blue ones! Here!

Answer from Alexey 11[guru]
Unfortunately it is so

Answer from Larisa Pavlova[guru]
no, not always, my eyes are gray and my husband’s are brown, our daughter’s eyes are gray like mine

Answer from EYES GREEN KNEES BLUE[guru]
In our case, the brown one won))) as you know, I have green eyes))

Answer from Diver[active]
not always but often

Answer from N.[guru]
We went through this at school, there are calculations on the power of probability, open the textbook “General Biology”.)

Answer from Yatyana[guru]
I have brown eyes, my husband has blue eyes, but my daughter still has blue eyes like her husband, which means that brown ones do not always dominate

Answer from Olka[newbie]
Not always!! ! A child does not necessarily inherit a dominant gene, but can also inherit a recessive one if it was present in previous generations). And we have brown-eyed parents and a blue-eyed daughter))

Answer from Anna Zilina[active]
won against us. My husband has brown eyes, my daughter also has brown eyes.

Answer from Kisa[expert]
Biology textbook for 9th grade. No not always.

Answer from ~Give me the Crown, Darling~[guru]
not always. my father is brown, and my mother is green

Answer from MarS[guru]
My wife and I have brown eyes, and my daughter has blue eyes, like her grandfather’s. AND.. . such a paradox. Until I was seven years old, my eyes were blue, and then they suddenly turned brown, that is, they became caried-dominated:.... (my father had blue eyes, my mother had brown eyes).

Answer from Irina I[guru]
Not always.

Answer from Hyperv strat[newbie]
We cannot isolate all alleles. Compared to all common alleles, it wins. But what if there is such a gray-brown-crimson color that its allele is more dominant? It's impossible to say for sure.

Answer from Vita[guru]
not always

Answer from Lyubov Semyonova[guru]
My eyes are green, my husband's are brown, and my daughter's are blue.

Answer from [email protected] [guru]
No. I have brown eyes, but our dad has blue eyes and our daughter has blue eyes.

3) One of the forms of glaucoma is determined by a dominant autosomal gene, and the second has an autosomal recessive type of inheritance. These genes are located on different pairs of chromosomes.
What is the probability of having a sick child if both parents are diheterozygous?

4) The gene for black color in cats is sex-linked. The other allele of this gene corresponds to the red color; heterozygous animals have a spotted ("tortoiseshell") coloration.
What will be the offspring from crossing a “tortoiseshell” cat with a ginger cat?

5) The forensic medical examination is tasked with finding out whether the boy in the family is his own or adopted. A blood test of the husband, wife and child showed: the wife is Rh-AB-IV blood type, the husband is Rh+O (I) blood type, the child is Rh-B (III) blood type.
What conclusion should the expert give and on what is it based?

6) When crossing a brown Great Dane with a white one, all the offspring are white. When breeding the resulting offspring "in themselves" we got 40 white, 11 black and 3 brown.
What type of gene interaction determines the inheritance of coat color in Great Danes? What is the genotype of the parents and offspring?

7) In chickens, striped color is due to the sex-linked dominant (B), and the absence of such striping is due to its recessive alleles (c). The presence of a crest on the head is a dominant autosomal gene (C), and its absence is a recessive allele (c). Two striped, combed birds were crossed and produced two chicks: a striped cockerel with a comb and a non-striped hen without a comb. Indicate the genotypes of the parental forms and offspring.

1) In humans, the gene for curly hair (A) dominates over the gene for smooth hair (a), and the gene for normal hearing (B) dominates over the gene for deaf-muteness (c). In a family where the parents are good

heard; but one has smooth hair and the other has curly hair, a deaf child was born with smooth hair. Their second child heard well and had curly hair.
What is the probability of having a deaf child with curly hair in such a family?

2) The gene for brown eyes is dominant over the gene for blue eyes. A brown-eyed man whose parent had blue eyes married a brown-eyed woman whose father had blue eyes and whose mother had brown eyes.
What kind of offspring can be expected from this marriage?

in humans, the gene for brown eyes dominates in humans, the gene for brown eyes dominates over the gene that determines blue eye color, and the gene that determines the ability to perform better

Right-handedness predominates over the left-handedness gene. What is the probability of having blue-eyed, left-handed children from the marriage of two diheterozygous parents?

in humans, the gene for brown eyes dominates the gene causing blue eyes, a blue-eyed man, one of whose parents has brown eyes, marries

a brown-eyed woman whose father has brown eyes and whose mother has blue eyes. What kind of offspring can be expected from this marriage.

1. A blue-eyed man, whose parents had brown eyes, married a brown-eyed woman, whose father had blue eyes and whose mother had blue eyes.

brown. What kind of offspring can be expected from this marriage if it is known that the gene for brown eyes dominates the gene for blue eyes?
2. There were two brothers in the family. One of them, a patient with hemorrhagic diathesis, married a woman also suffering from this disease. All three of their children (2 girls and 1 boy) were also sick. The second brother was healthy and married a healthy woman. Of their four children, only one was sick with hemorrhagic diathesis. Determine which gene determines hemorrhagic diathesis.
3. In a family where both parents had normal hearing, a deaf child was born. Which trait is dominant? What are the genotypes of all members of this family?
4. A man suffering from albinism marries a healthy woman whose father suffered from albinism. What kind of children can be expected from this marriage, given that albinism is inherited in humans as an autosomal recessive trait?

Eye color: how it is passed on from parents to child. Calculate the child's eye color.

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Eye color: from grandparents to our grandchildren: how it is transmitted genetically.
Tables for calculating the eye color of an unborn child.

During pregnancy, many parents are eager to find out what eye color their unborn child will have. All answers and tables for calculating eye color are in this article.

Good news for those who want to pass on their exact eye color to their descendants: it is possible.

Recent research in the field of genetics has discovered new data on the genes that are responsible for eye color (previously 2 genes were known that were responsible for eye color, now there are 6). At the same time, today genetics does not have answers to all questions regarding eye color. However, there is a general theory that, even with the latest research, provides a genetic basis for eye color. Let's consider it.

So: every person has at least 2 genes that determine eye color: the HERC2 gene, which is located on human chromosome 15, and the gey gene (also called EYCL 1), which is located on chromosome 19.

Let's look at HERC2 first: humans have two copies of this gene, one from their mother and one from their father. HERC2 can be brown and blue, that is, one person has either 2 brown HERC2 or 2 blue HERC2 or one brown HERC2 and one blue HERC2:

(*In all tables in this article, the dominant gene is written with a capital letter, and the recessive gene is written with a small letter, eye color is written with a small letter).

Where does the owner of two blue ones come from? HERC2 green eye color - explained below. In the meantime, some data from the general theory of genetics: brown HERC2 - dominant, and blue is recessive, so the carrier has one brown and one blue HERC2 eye color will be brown. However, to his children the bearer of one brown and one blue HERC2 with a 50x50 probability it can transmit both brown and blue HERC2 , that is, the dominance of brown has no effect on the transfer of the copy HERC2 children.

For example, a wife has brown eyes, even if they are “hopelessly” brown: that is, she has 2 copies of brown HERC2 : All children born to such a woman will be brown-eyed, even if the man has blue or green eyes, since she will pass on one of her two brown genes to the children. But grandchildren can have eyes of any color:

So, for example:

HERC2 about the mother's t is brown (the mother, for example, has both HERC2 brown)

HERC2 from the father - blue (father, for example, has both HERC2 blue)

HERC2 The child has one brown and one blue. The eye color of such a child is always brown; at the same time your HERC2 he can pass on the blue color to his children (who can also receive it from the second parent HERC2 blue and then have eyes either blue or green).

Now let's move on to the gene gay: it comes in green and blue (blue, grey); each person also has two copies: a person receives one copy from his mother, the second from his father. Green gay is the dominant gene, blue gay - recessive. A person thus has either 2 blue genes gay or 2 green genes gay or one blue and one green gene gay . At the same time, this affects the color of his eyes only if he has HERC2 from both parents - blue (if he received brown from at least one of the parents HERC2 , his eyes will always be brown).

So, if a person received blue from both parents HERC2 , depending on the gene gay his eyes can be the following colors:

gay gene: 2 copies	Human eye color
Green and Green	green
Green and blue	green
blue and blue	blue

General table for calculating a child's eye color, brown eye color is designated "K", green eye color is designated "Z" and blue eye color is designated "G":

HERC2	Gey	eye color
QC	ZZ	brown
QC	Zg	brown
QC	GG	brown
Kg	ZZ	brown
Kg	Zg	brown
Kg	GG	brown
yy	ZZ	green
yy	Zg	green
yy	GG

Problem 1. In humans, the gene for brown eyes is dominant over the gene for blue eyes. What is the probability of having blue-eyed children in a family where the mother had blue eyes and the father had brown eyes, and it is known that he is heterozygous for this trait?

Solution: Let's write down the crossing scheme.

R: ♀ aa x ♂ Aa

blue brown

G: (a) (A) , (a)

brown blue

Answer: the probability of having a blue-eyed child is 50%.

Task 2. Phenylketonuria is inherited as an autosomal recessive trait. In a family where both parents were healthy, a child with phenylketonuria was born. What is the probability that the second child in this family will also be sick?

Solution. R: ♀ A- x ♂ A-

Reasoning. Since both parents are healthy, they can have both the AA and Aa genotypes. Since the first child in this family was sick, his genotype is aa. According to the gamete purity hypothesis, the body receives one allele of a gene from the father, and the other from the mother. Consequently, both parents are heterozygous for the analyzed trait - Aa.

Now you can determine the probability of having a second child with a patient:

R: ♀ Aa x ♂ Aa

Norm norm

G: (A), (a) (A), (a)

F 1: AA, 2 Aa, aa

Normal normal phenylketonuria

Thus, 75% of children will be healthy, and 25% will be sick.

Answer: 25%.

Task 3. In some breeds of cattle, polledness is dominant over hornedness.

A) When crossing polled and horned animals, 14 horned and 15 polled offspring were born. Determine the genotypes of the parental forms.

C) As a result of crossing horned and polled animals, all 30 offspring were polled. Determine the genotypes of the parental forms.

C) Crossing polled animals with each other produced 12 polled and 3 horned calves. Determine the genotypes of the parental forms.

Solution. The genotypes of the parents can be determined by segregation in the offspring. In the first case, the splitting was 1:1, therefore there was an analyzing cross:

R: ♀ Aa x ♂ aa

polled horniness

G: (A), (a) (a)

polled hornedness

In the second case, there was uniformity of the offspring, therefore homozygous horned and polled animals were crossed:

R: ♀ AA x ♂ aa

Norm norm

polled

In the third case, a 3:1 split occurred, which is only possible when crossing two heterozygotes:

R: ♀ Aa x ♂ Aa

polled polled

G: (A), (a) (A), (a)

F 1: AA, 2 Aa, aa

polled hornedness

75% - polled

25% - horned

Answer: A) Aa and aa

B) AA and aa

C) Aa and Aa

Task 4. In humans, brown eyes dominate over blue ones, and right-handedness dominates over left-handedness.

1. What is the probability of having a left-handed, blue-eyed child in a family where the mother is blue-eyed and right-handed (although her father was left-handed), and the father has brown eyes and is predominantly left-handed, although his mother was blue-eyed and right-handed?

2. In a family of brown-eyed, right-handed people, a left-handed child with blue eyes was born. What is the probability that your next child will be right-handed and have blue eyes?

♂--вв ♀ааВ-

R: ♀ aaB- x ♂A-bb

Reasoning. First you need to determine the genotypes of the parents. Since the woman’s father was left-handed, she is therefore heterozygous for the B gene; the man is heterozygous for gene A, since his mother had blue eyes.

Examination. Let's write down the crossing scheme:

R: ♀ aaVv x ♂Aavv

Blue, right Car., lion.

G: (аВ), (ав) (Ав), (ав)

F 1: AaBv, aaBv, Aavv, aavv

Kar., right. Goal, right Kar, lion. Blue, lion

Answer: the probability of having a blue-eyed, left-handed child is 25%.

R: ♀ A-B- x ♂ A-B-

Brown-eyed Brown-eyed

Right-handed right-handed

Blue-eyed lefty

Reasoning. Since, according to the gamete purity hypothesis, the organism receives one gene allele from one parent, and the other from the other, then both parents are heterozygous for both pairs of analyzed genes; their genotype is AaBb.

P: ♀ AaBv x ♂ AaBv

Kar. Right Kar. Right

Thus, the probability of having the next right-handed child with blue eyes (genotype aaBb or aaBB) is 3/16 (or 18.75%).

In humans, the gene for brown eyes is dominant over the gene causing blue eyes. A blue-eyed man, one of whose parents had brown eyes,

married a brown-eyed woman whose father had brown eyes and whose mother had blue eyes. What kind of offspring can be expected from this marriage?

In humans, the gene for brown eyes dominates the gene causing blue eyes. A blue-eyed man, one of the parents who had brown eyes, got married

on a brown-eyed woman whose father had brown eyes and his mother had blue eyes. What kind of offspring can be expected from this marriage?

No. 2. What kind of offspring can you expect?

from crossing a cow and a bull,
heterozygous for coat color?
Problem No. 3. Guinea pigs have frizzy hair
wool is determined by a dominant gene, and
smooth - recessive.
1. Crossing two curled pigs between
produced 39 individuals with shaggy fur and
11 smooth-haired animals. How many among
individuals having a dominant phenotype,
must be homozygous for this
sign?
2. A guinea pig with shaggy fur
crossed with an individual having a smooth
wool, gave birth to 28 frizzy and 26
smooth-haired offspring. Define
genotypes of parents and offspring.
Task No. 4. An offspring was obtained at the fur farm
in 225 minks. Of these, 167 animals have
brown fur and 58 bluish-gray minks
coloring. Determine the genotypes of the original
forms, if it is known that the gene is brown
coloring dominates the gene,
defining bluish-gray color
wool
Problem No. 5. A person has a gene for brown eyes
dominates the gene causing
Blue eyes. Blue-eyed man, alone
of whose parents had brown eyes,
married a brown-eyed woman who
the father had brown eyes, and the mother had blue eyes.
What kind of offspring can be expected from this
marriage?
Problem No. 6. Albinism is inherited in
human as a recessive trait. In family,
where one of the spouses is an albino, and the other has
pigmented hair, have two children.
One child is albino, the other is
dyed hair. What is the probability
birth of the next albino child?
Problems on di- and polyhybrid crossing
Problem No. 8. Cattle have a gene
polledness dominates the horned gene, and
gene for black coat color - above the gene
red color. Both pairs of genes are located
in different pairs of chromosomes.
1. What will the calves turn out to be like if they are crossed?
heterozygous for both pairs
signs of a bull and a cow?
2. What kind of offspring should be expected from
crossing a black polled bull,
heterozygous for both pairs of traits,
with a red horned cow?
Problem No. 9. Dogs have black fur.
dominates the coffee, and the short coat
- over the long one. Both pairs of genes are in
different chromosomes.
1. What percentage of black shorthairs
puppies can be expected from crossing two
individuals heterozygous for both traits?
2. The hunter bought a black dog with a short
wool and wants to be sure that it is not
carries genes for long, coffee-colored hair.
Which partner according to phenotype and genotype do you need?
select for crossing to check
genotype of the purchased dog?
Problem No. 10. A person has a gene for brown eyes
dominates the gene that determines
development of blue eye color, and the gene
conditioning the ability to better master
right hand, dominates the gene,
determining the development of left-handedness. Both
pairs of genes are located in different
chromosomes. What kind of children can be if
Are their parents heterozygous?