Presentation "Hereditary diseases". Sex-linked diseases Download presentation hereditary sex-linked diseases

It has 23 pairs of chromosomes, of which 22 pairs are autosomal, and the 23rd is sexual. In women, the 23rd pair is XX, in men - XY. The Y chromosome plays a decisive role in determining sex. Human WomanMan Has only X chromosomes (one from the mother, the other from the father) Carries only X chromosomes Has an X chromosome from the mother and a Y -chromosome from father Can carry both X chromosomes and Y chromosomes X XY

SEX-LINKED TRAITS Sex-linked inheritance is the transmission of genes located on the sex chromosomes and the inheritance of traits controlled by these genes. Sex-linked traits are non-sexual characteristics whose genes are located on the sex chromosomes. There are usually more of them in the X-chromosomes. chromosome

HERITABLE SEX-LINKED DISEASES Gene diseases and abnormalities Chromosomal diseases Depend on the sex chromosomes of the parent organisms. Disorders of genetic processes Do not depend on parents, occur due to disturbances in the divergence of chromosomes

Smirnova Z. M.

Genetics of sex

• Chromosome complex of a woman 44 autosomes + XX heterochromosomes.
• For a man - 44A + XY = 46.
• Sex is determined at the time of fertilization and depends on the combination of sex chromosomes in the gamete. Since gametes with X- and Y-chromosomes are formed in men during meiosis in equal quantities, the sex ratio is 1:1

• A sex whose individuals have identical sex chromosomes and form 1 type of gametes is called homogametic; a sex whose individuals have different sex chromosomes and form 2 types of gametes is called heterogametic.

P XX x XY

G X X Y

F1 XX XY

Homogametic sex Heterogametic sex

Sex chromosomes determine the development of primary and secondary sexual characteristics

Primary sexual characteristics - gonads and organs, take a direct part in the processes of reproduction (gametogenesis, insemination, fertilization).

Secondary sexual characteristics are not directly involved in reproduction. Develop under the influence of sex hormones

(in a person aged 11-15 years). These are features of the skeleton, subcutaneous fat, hair, timbre of voice, and behavior.

Sex-linked inheritance

• Sex chromosomes have homologous regions (inheritance

the genes contained in them do not differ from the autosomal one).

• But there are also non-homologous regions in the X chromosome and Y chromosome.

X-linked traits are caused by genes located in a non-homologous region of the X chromosome

(color blindness, hemophilia, etc.).

Holandric characteristics are caused by genes located in a non-homologous region of the Y chromosome (ichthyosis, hairiness of the middle phalanges of the fingers, etc.).

A region that does not have a homolog on the Y chromosome

A region that does not have a homologue on the X chromosome

Homologous regions of sex chromosomes

Sex-linked inheritance

• Sex chromosomes, in addition to genes that determine sex, contain genes

not related to gender. The signs they define are called gender-linked characteristics.

• If a gene is linked to the X chromosome and is recessive - X h (hemophilia, color blindness), then in women it can only manifest itself in

homozygous state (X h X h ).

• Men do not have a second X chromosome, and there is no homologous chromosome in the Y chromosome. section of the X chromosome, so in men these genes always appear and are dominant for them (X h Y).

• The phenomenon when a gene (hemophilia, color blindness in men) is present in an individual not in

form of a pair of alleles, and in singular called hemizygous condition.

• Males are hemizygous for genes located in

X chromosome. Therefore, recessive hereditary diseases caused by genes such as hemophilia, color blindness, more often found in men.

Sex-linked inheritance

• If the gene is located on the X chromosome (gene for hemophilia, color blindness, etc.).

It can only be passed on from father to daughters.

• From the mother it is distributed equally among daughters and sons.

X H X h

x X H Y

X H

X H

X h

F 1

X h Y

X H Y

X H X H ;

X h X H ;

X h Y

X H X h

X H Y;

X H X H

X-linked recessive gene

Dominant gene (normal)

Dominant gene (normal)

Sick

Healthy

Carriers

X h X H ;

X h X H ;

X H Y;

X H Y ;

X h X H ;

X h Y

X H Y;

X H X H

Hemophilia

X H X h

X H X h x X H Y

X H

X h

X H

X H X H ; X H Y; X h X H ; X h Y

Sex-linked traits

Normal color perception

color blindness

X d X d

color blindness

X D Y – norm

X d Y

X D X d

or normal

X D X D

Sex-linked traits

If the gene is linked to the Y chromosome (hairy ears, webbing between toes), then it can only be passed on from father to sons, because A sperm with a Y chromosome, fertilizing an egg with an X sex chromosome, determines the development of the embryo according to the male type.

XX x XY Z

Y Z

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Description of the presentation Presentation Sex-linked inheritance on slides

Map of the human chromosome set The human karyotype contains 22 pairs of chromosomes, identical in males and females. female body, and one pair of chromosomes that distinguishes both sexes. Chromosomes that are the same in both sexes are called autosomes. The chromosomes by which male and female sexes differ from each other are sex chromosomes or heterochromosomes. . The sex chromosomes in women are the same, they are called XX chromosomes. Men have an XX chromosome and one YY chromosome.

Genetic explanation of the sex ratio in humans As a result of gametogenesis, all egg cells have one X chromosome, and sperm cells have two types of gametes: half carry the X chromosome, half carry the YY chromosome. The sex of the offspring depends on which sperm fertilizes the egg. If the egg is fertilized by a sperm carrying the X chromosome, the female body develops. If an egg is fertilized by a sperm carrying the YY chromosome, a male organism develops. Females (XX X) have one X chromosome from their father and one X chromosome from their mother. A male (XYXY) receives an X chromosome only from his mother. This determines the peculiarity of inheritance of genes located on the sex chromosomes. In dioecious organisms, the sex ratio is usually 1:1, i.e. males and females are equally common

Chromosomal sex determination In humans, most vertebrates, many insects and dioecious plants, the homogametic sex is female (XXXX), and heterogametic is male (XY). In birds, butterflies, reptiles, and tailed amphibians, the homogametic sex is the male sex (XXXX), and the heterogametic sex is the female sex (XY). The sex chromosomes in these species are sometimes designated by the letters WW and and ZZ, with males designated by the symbols ZZZZ and females by WZWZ. . In Orthoptera (grasshoppers), the homogametic sex is the female sex (XXXX), and the monogametic sex is the male sex (XO). A sex containing two X chromosomes in its cells is called homogametic, and a sex containing both X and YY chromosomes is called heterogametic. .

Chromosomal sex determination Haploidy is widespread in bees and ants. These organisms do not have sex chromosomes: females are diploid and males are haploid. In some animals, sex determination depends on external conditions. For example, in the sea worm Bonelia, individuals that remain free-swimming in the larval stage become females, and larvae attached to the body of an adult female become males as a result of the muscularizing effect of a hormone secreted by the female.

Sex-linked traits Traits inherited with sex chromosomes XX and Y are called sex-linked. . The YY chromosome is called genetically inert or genetically empty, since it contains very few genes. In humans, the Y chromosome contains a number of genes that regulate spermatogenesis, manifestations of histocompatibility antigens that affect the size of teeth, etc. There are known anomalies associated with the YY chromosome, which are transmitted from the father to all sons (scaly skin, webbed fingers, heavy hair growth on the ears). Y X Y

Detailed map Human X chromosomes More than 370 diseases linked to the X chromosome are known. Since males have one X chromosome, all genes localized on it, even recessive ones, immediately appear in the phenotype.

Sex-linked inheritance Color blindness, partial color blindness, a type of color vision disorder. This disease was first described in 1794. Color blindness occurs in 8% of men and 0.5% of women. When one of these elements is lost, partial color blindness occurs - dichromasia. . Using these tables, color perception can be impaired. In table No. 1, people with normal vision see the number 16. People with acquired visual impairment have difficulty or do not at all distinguish the number 96 in table No. 2.

Hemophilia is a sex-linked recessive disease in which the formation of factor VIII, which accelerates blood clotting, is impaired. The gene that determines the synthesis of factor VIII is located in a region of the X chromosome that does not have a homolog, and is represented by two alleles - a dominant normal and a recessive mutant. Bleeding in hemophilia occurs with early childhood. Even mild bruises cause extensive hemorrhages - subcutaneous, intramuscular. Cuts, tooth extraction, etc. are accompanied by life-threatening bleeding and can cause death.

“Royal disease” This pathological mutation in the F 8C gene was in the genotype of the heir to the royal throne, Russian Tsar Alexei. Hemophilia A is a severe hereditary disease that affects almost exclusively males. On average, one out of 10,000 boys is born with this pathology, and only in 70% of cases can one find indications of hereditary transmission of the mutant gene in his pedigree. This means that for every third family in which such a misfortune happened, the latter is a complete surprise.

Pedigree of descendants Queen of England Victoria. It is believed that the hemophilia gene arose as a result of a mutation in Queen Victoria herself or one of her parents.

Inheritance pattern of hemophilia Mother is a carrier of the hemophilia gene (XHXh), father is healthy (XNU). Females heterozygous for any of the sex-linked traits are phenotypically normal, but half of their gametes carry a recessive gene. Despite the father having a normal gene, sons of carrier mothers have a 50% chance of developing hemophilia.

Answer questions 1. 1. What are the chromosomes that are the same in both sexes called? 2. 2. Which chromosomes are called sex or heterochromosomes? 3. 3. What determines the sex of the future offspring? 4. 4. What sex is called homogametic and why? 5. 5. Which sex is called heterogametic? 6. 6. Which sex is homogametic in humans, most vertebrates, many insects and dioecious plants? 7. 7. What sex is homogametic in birds, butterflies, reptiles, and tailed amphibians? 8. 8. What traits are called sex-linked? 9. 9. Why do male individuals immediately exhibit recessive traits associated with the X chromosome in their phenotype? 10. Give examples of diseases linked to sex?

Tasks on the topic “Sex-linked inheritance” 1. 1. Enamel hypoplasia is inherited as a dominant trait linked to the X chromosome. In a family where both parents suffered from this anomaly, a son was born with normal teeth. What will the second son be like? 2. 2. In humans, pseudohypertrophic muscular dystrophy ends in death at 10–20 years of age. In some families, the disease is influenced by a sex-linked recessive gene. The disease has been reported only in boys. If affected boys die before childbearing, why does this disease not disappear from the population? 3. 3. Hypertrichosis (hair growth on the edge of the auricle) is inherited as a trait linked to the Y chromosome. What is the probability of having children and grandchildren with this trait in a family where the father and grandfather had hypertrichosis?

• Genetics of sex. Sex-linked inheritance.
• Genetics of sex. Sex-linked inheritance.
• Genetics of sex. Sex-linked inheritance.
• Genetics of sex. Sex-linked inheritance.

“We all stand on the shoulders of our ancestors”

Biology teacher MBOU "Levkovskaya Secondary School No. 7

Chernakova Nina Evgenievna

… all happy families are alike, but every unhappy family is unhappy in its own way

L.N. Tolstoy

• Map of human chromosome set

A human karyotype contains 22 pairs of chromosomes, identical in male and female organisms, and one pair of chromosomes, which distinguishes both sexes. Chromosomes that are the same in both sexes are called autosomes. The chromosomes by which male and female sexes differ from each other are sex or heterochromosomes. The sex chromosomes in women are the same, they are called X chromosomes. Men have an X chromosome and one Y chromosome.

Customer:

Sex ratio

In humans, most vertebrates, many

In insects and dioecious plants, the homogametic sex is the female sex (XX), and the heterogametic sex is the male sex (XY).

In birds, butterflies, reptiles, and tailed amphibians, the homogametic sex is the male sex (XX), and the heterogametic sex is the female sex (XY). The sex chromosomes in these species are sometimes designated by the letters W and Z, with males designated by the symbols ZZ and females by WZ.

In Orthoptera (grasshoppers) homogametic

The sex is female (XX), and the monogametic sex is male (XO).

Haploidy is widespread in bees and ants. These organisms do not have sex chromosomes: females are diploid and males are haploid.

In some animals, sex determination depends on external conditions. For example, in the sea worm Bonelia, individuals that remain free-swimming in the larval stage become females, and larvae attached to the body of an adult female become males as a result of the muscularizing effect of a hormone secreted by the female.

Traits inherited with sex chromosomes X and U, got the name interlocked with the floor

Inheritance of diseases linked to X- chromosome

* classic hemophilia

*absence of gonads

*color blindness (color blindness)

*hypoplasia (darkening of teeth)

*hydrocephalus

• Inheritance linked to - chromosome

* hypertrichosis

*webbed

• Detailed map of the human X chromosome

More than 370 diseases associated with

X chromosome.

Since males have one X chromosome, all genes localized on it, even recessive ones, immediately manifest themselves in the phenotype .

• Clinical signs:
• sub- and intradermal bleeding, hemorrhages in large joints, subcutaneous and intermuscular hematomas, hematuria, severe bleeding from injuries. Cause: deficiency of antihemophilic globulin.
• Inheritance type: X - recessive
• Population frequency– 1: 2500 (boys)

Inheritance of hemophilia

X X

X Y

Female carrier

Healthy man

X Y

X Y

X X

Healthy daughter

Bearer daughter

Healthy son

Sick son

Pedigree of the descendants of Queen Victoria of England. It is believed that the hemophilia gene arose as a result of a mutation in Queen Victoria herself or in one of her parents .

Pattern of inheritance of hemophilia

Mother is a carrier of the hemophilia gene ( XHXh ), father is healthy (KhNU).

Females heterozygous for any of the sex-linked traits are phenotypically normal, but half of their gametes carry a recessive gene. Despite the father having a normal gene, sons of carrier mothers have a 50% chance of developing hemophilia.

• In people's minds, any mention of hemophilia is primarily associated with the image of Tsarevich Alexei - the son of the last Russian Emperor Nicholas II.
• Alexey was sick with hemophilia, having received it from his mother, Empress Alexandra Feodorovna, who inherited the disease from her mother Princess Alice, who in turn received it from her mother, Queen Victoria

Hemophilia.

a hereditary disease characterized by a lifelong disorder of the blood clotting mechanism. In 80% of cases this is due to the absence or insufficiency of antihemophilic globulin in the blood plasma. As a result, blood clotting time is prolonged and patients suffer from severe bleeding even after minimal trauma.

Inheritance of hemophilia in the family of Tsar Nikolai Alexandrovich

Nicholas II

Alexandra

Anastasia

• Sex-linked inheritance
• Sex-linked inheritance
• Sex-linked inheritance
• Sex-linked inheritance

Color blindness, partial color blindness, is a type of color vision disorder. This disease was first described in 1794. Color blindness occurs in 8% of men and 0.5% of women.

When one of these elements is lost, partial color blindness occurs - dichromasia.

Using these tables, color perception can be impaired. In table No. 1, people with normal vision see the number 16.

People with acquired visual impairment have difficulty or do not distinguish the number 96 in Table No. 2 at all.

• In humans, the gene for color blindness is recessive and is located on the X chromosome. In what case can a colorblind man have a colorblind son?

Solution

M.colorblind

D. colorblind

• Clinical signs: increase in head volume, expansion of the ventricles of the brain; thinning and divergence of the skull bones, disproportion of the brain and facial parts of the skull, strabismus, mental retardation and developmental delay, movement and coordination disorders, nystagmus, atrophy of the white matter of the brain.
• Inheritance type: X-recessive.
• Population frequency – 1: 2000

PEDIGREE WITH X-LINKED TYPE OF INHERITANCE

• 1. Only boys on their mother’s side are affected.
• 2. The proband’s parents are healthy.
• 3. The sick man does not transmit the disease, but all his daughters are carriers.
• In a marriage of a carrier woman with a sick man, 50% of daughters and 50% of sons are sick.

Traits linked to the y chromosome

at -the chromosome is called genetically inert or genetically empty, since it contains very few genes.

In humans, the Y chromosome contains a number of genes that regulate spermatogenesis, the manifestation of histocompatibility antigens, affecting the size of teeth, etc.

Anomalies associated with Y -chromosome, which are passed on from the father to all sons (scaly skin, webbed fingers, heavy hair growth on the ears).

• Clinical signs: Excessive hair growth on all parts of the body except the palms and soles. Since the Middle Ages, only 50 cases of congenital hypertyrchiosis have been recorded. There are no other developmental abnormalities. Local hypertrichosis can occur with metabolic disorders.
• Type of inheritance: AD. Population frequency unknown.

• Hypertrichosis is inherited as a trait linked to the y chromosome.

What is the probability of having children with this anomaly in a family where the father has hypertrichosis?

Functional disorders

Action

gametes

alcohol

Slowing embryo growth

nicotine

mutations

Inhibits the development of nerve cells

Narcotic substances

radiation

x-ray

radioactive

ultraviolet

Sun, ultrasound, fluorography, x-ray examination, computer, cell phone, household appliances (microwave, TV)

cell

mutation

Damaged DNA

• Phenylketonuria(PKU) is a congenital disease caused by a violation of the transition of phenylalanine to tyrosine and leading to mental retardation.
• Clinical picture Neurological and mental disorders Mental retardation Increased excitability in childhood Specific gait Specific posture and sitting position Unusual position of the limbs Stereotypical movements Increased tendon reflexes Seizures Skin changes Dryness Eczema Vomiting in the newborn period Specific mouse body odor.

• 47 chromosomes – extra X chromosome – XX Y
• Seen in young men
• High growth
• Violation of body proportions (long limbs, narrow chest)
• Developmental delay
• Infertility

• Shereshevsky-Turner syndrome (45; X0) is observed in women. It manifests itself in delayed puberty, underdevelopment of the gonads, and infertility.
• Women with Shereshevsky-Turner syndrome are short, their body is disproportionate - the upper body is more developed, the shoulders are wide, the pelvis is narrow - lower limbs shortened, short neck with folds, “Mongoloid” eye shape and a number of other features.

• Down syndrome occurs when the baby's cells have not 46, but 47 chromosomes. Such children are mentally retarded, 50% have heart defects, a weak immune system... In a newborn, the disease can be diagnosed based on the characteristic appearance child: a rounded skull, a slanted back of the head, an oblique eye shape, a wide bridge of the nose, an additional eyelid, light gray spots on the iris, a “Gothic” palate, small ears. The mouth is usually half open; the tongue is thick, often protrudes from the mouth, covered with transverse grooves; the hand is wide, the fingers and toes are shortened, the little finger is often curved; sometimes the fingers are fused (partial or complete syndactyly). The palm often shows a complete transverse fold (monkey fold).

• Remember! The health of your future children is in your hands!
• Remember!
• The health of your future children is in your hands!

You have a choice:

stay healthy and live without problems or...

• You have a choice: stay healthy and live without problems or...

Remember that the health of your future children depends on your health.

• In humans, pseudohypertrophic muscular dystrophy ends in death at 10–20 years of age. In some families, the disease is influenced by a sex-linked recessive gene. The disease has been reported only in boys. If affected boys die before childbearing, why does this disease not disappear from the population?

Concepts: Hereditary diseases– diseases
human, caused by chromosomal and
gene mutations.
Sex-linked inheritance -
inheritance of any gene located on the sex chromosomes. On
following signs that appear only in wasps
of both sexes, but not determined by genes, is found
located on the sex chromosomes is called sex-limited inheritance.

Inheritance linked to X-
chromosome, called the inheritance of genes in the case
e, when male sex is heterogametic and characterized by
is characterized by the presence of a Y chromosome (XY), and female individuals are homogametic
we have two X chromosomes (XX). This type of inheritance has
All mammals (including humans) eat
Most insects and reptiles.

Sex-linked inheritance of the disease
associated mainly with the sex X chromosome.
Most hereditary diseases (those or
other pathological signs) associated with
gender and are transmitted recessively. Such diseases
there are about 100.
A woman carrier of a pathological
the trait itself does not suffer, since a healthy X chromosome dominates and suppresses the X chromosome with
pathological sign, i.e. compensates
inferiority of this chromosome. Wherein
The disease manifests itself only in males.

The X-linked recessive type transmits: color blindness (red-green blindness), optic nerve atrophy,

Curly hair syndrome

Colorblindness

According to the dominant X-linked type
hypophosphatemic rickets is transmitted (not amenable to
treatment with vitamins D2 and D3), brown tooth enamel and
etc. These diseases develop in both male and female
female.
Diseases with a hereditary predisposition arise
in persons with a minor disability of one or another
other hereditary structure, which, in conditions
normal life activity is not clinically manifested
(because it can compensate).
However, under the influence of various unfavorable
external influences (certain significant
loads) this hereditary inferiority is realized
in the form of a certain disruption of metabolic processes,
structure and function that can lead to the development
the corresponding disease.

Rickets

General classification of hereditary diseases

Hereditary diseases
Multigene
Autosomal dominant
Autosomal recessive
Interlocked with the floor
Chromosomal
genomic mutations
chromosomal mutations
Polygenic

Significant role in hereditary
predispositions usually play altered
constitution and reactivity of the body, as well as
various negative influences of the external environment and
etc.
These diseases represent a fairly extensive
group (according to WHO, more than 90%)
hereditary pathologies that differ
variety of its manifestations.
Diseases with hereditary predisposition
can be monogenic, but more often polygenic (i.e.
e. caused by a mutation of one, respectively, or
many genes) and are caused by various pathogenic
body factors (dirty air, water, food;
intolerance to milk, dairy products,
medications, etc.).

It is no coincidence that these diseases are called
multifactorial. For example, often found in
different countries of the world intolerance to different
people milk, dairy products and dairy
food, which is usually due to the autosomal recessive trait of galactose intolerance
due to the absence or inhibition of beta-galactosidase in
intestines of homozythotic organisms.
To diseases with hereditary predisposition
include DIABETES MELLITUS, peptic ulcer
stomach and duodenum, arterial
hypertension, atherosclerosis, gout, tuberculosis,
bronchial asthma, schizophrenia, psoriasis,
collagenosis and other forms of pathology.