How to quickly determine whether a genetic disease is associated or unaccompanied is an effective me

When a mother is sick, her daughter is sick.

Or if the father is sick, the son will be sick.

It is a non-concomitant genetic disease.

Answer]::Step 1: Confirm or rule out whether it is inherited with Y, if it is inherited with Y, then all the patients are male.

Step 2: Judge the explicit implicitness, the creation of the implicit is implicit, and the creation of the middle is not the explicit.

Step 3: Determine whether it is on the autosomal or X chromosome.

If it is accompanied by x recessive genetic disease, the father and son must be sick, and if the father and son are not sick, it is often hidden.

If it is accompanied by x dominant genetic disease, the mother and daughter must be sick, and if the mother and daughter have non-slag residual disease, it is often obvious.

Creating something out of nothing is hidden, and the hidden disease is seen as a female disease, and the female father (son) is not sick can be excluded with x hidden.

If there is no dominant middle disease, the obvious disease is seen as a male disease, and the male mother (female) is not sick can be excluded with x manifestation.

1 First determine the explicit implicitness:

Out of nothing, there is implicitness, "there is nothing out of the obvious".

2. Determine the location of the pathogenic gene

Creating something out of nothing is hidden, and the daughter's illness is often hidden" There is no dominance in the middle birth, and the daughter is normal and often obvious" Maternal disease, child disease, female disease, father's disease, male patients are more likely than women" Most likely to be "X hidden" (female disease and male disease must be sick) Father disease, female disease, child disease and mother disease, female patients are more likely than men" Most likely to be "X obvious" (male disease and female disease must be sick).

3.Methods of dealing with the coexistence of autosomes and sex chromosomes:

When two or more pairs of traits controlled by genes on both sex chromosomes and autosomes are inherited: traits controlled by genes on sex chromosomes are treated as companion inheritance; Traits controlled by genes on autosomes are treated according to the law of segregation, and the law of free combination of genes as a whole.

Incidental genetic disorders refer to those genetic diseases in which the disease-causing gene is located on the X chromosome and is passed through them, so it is also called X-linked inheritance. Associated genetic disorders are also divided into sex-linked dominant inheritance and sex-linked recessive inheritance: X-linked dominant inheritance.

It occurs when a pair of alleles on the X chromosome are both disease-causing genes. Its genetic characteristics are: The onset is sex-related and is more common in males.

When the parents are normal, the boy may get the disease, and the causative gene must come from the mother, and the girl is normal, but 1 2 are carriers.

If a female patient is present, her father must be a patient and her mother is a carrier.

If the father is a patient, all the daughters born are carriers, and the sons are normal. If the mother is a patient, the daughter born is a carrier and the son is a patient.

The causative gene in male patients is passed down from the mother, also known as cross-inheritance. Brothers, uncles, cousins, maternal grandfathers, and nephews may also be patients due to cross-inheritance.

Sex-linked recessive inheritance.

The disease-causing gene is dominant and located on the X chromosome, and one of the alleles in a pair is the disease-causing gene. These disorders are rare. Its genetic characteristics are as follows: Women are more likely to get the disease, and men are less likely to get the disease.

One of the patient's parents must be the patient.

Both boys and girls may have children born to female patients, and the chances are 1 2;In the case of male patients, all daughters are born to patients and sons are normal.

It occurs for several generations.

I'll add to the brother who went upstairs: Also, if the gene is inherited with x recessive, then both boys and girls can get sick! 1 If it is a recessive combination of X and Y, it is a sick boy, and 2 If it is a dominant X and Y combination, then it is a boy who is not sick.

3 And if it is a combination of two recessive x, it is a sick girl, and 4 If it is a combination of one explicit and one hidden, then there is no sick girl! 5. If it's a combination of two explicit sexes, then it's a girl who is not sick! And a boy who is not sick does not have a disease-causing gene, but a girl who is not sick is not necessarily!

The girls in the 4 above are the ones with the disease-causing genes! Do you understand?

Companion inheritance has the characteristics of cross-inheritance.

There are original words in the book.

Normal people have.

There are 23 pairs of chromosomes, of which 22 pairs are both male and female, called autosomes (chromosome 1 22), and the other pair is different from male and female, that is, sex chromosomes, females are homogamous xx, males are heteromatous xy. If the gene that controls a trait or disease is located on an autosome, and the gene is dominant, it is called autosomal dominant inheritance; The inheritance of diseases or traits controlled by autosomal recessive genes is autosomal recessive inheritance. The so-called sex chromosome inheritance, if the inheritance of traits or diseases controlled by genes on the X chromosome is called X-linked inheritance, and there are also two types of dominant recessive, and the inheritance of traits or diseases controlled by genes on the Y chromosome is called Y-linked inheritance, because there will be no Yy type pairing at any time, so there is no dominant recessive distinction.

As for dominant and recessive, I think it can be explained in layman's terms: generally the genes that control traits are all one-to-one pairs, called alleles, one from the father and one from the mother. If these two genes are different, then only one of them will be manifested, and the other gene that is represented is relatively unrepresented, which is the dominant gene, and conversely, the unrerepresented gene is the recessive gene.

X sex chromosome dominant.

X sex chromosomes, recessive.

Y-chromosome inheritance.

Companion inheritance can be summarized as follows:

1.When the sex chromosomes of the homomatous sex (e.g., xx for mammals and ZZ for birds) transmit homozygous dominant genes, both F1 females and males are dominant. The segregation of the F2 trait showed 3 dominant characteristics

1 recessive; The segregation of the sexes is 1 female: 1 male. The sex of the recessive individual is the same as that of the grandparent recessive, i.e., the grandchildren of 1 2 have the same phenotypic characteristics as their maternal grandfathers.

2.When the sex chromosomes of the homogamous sex pass homozygous recessive genes, F1 is cross-inherited, that is, the mother's traits are passed on to the son, and the father's traits are passed on to the daughter, and in F2, the ratio of traits to sex is 1:1.

3.Traits determined by genes (specifically humans or mammals) that exist in the differential segments of the Y chromosome, or traits determined by genes carried by the W chromosome, are passed from father (or mother bird) to son (or female or female bird) only. Manifests as a special Y-linked (or W-linked) inheritance.

Hope it can help you

Genetic classification of companions:

The first type: with x dominant inheritance (there is no one on y.)

allele) - characterized by the fact that the child is diseased, and the mother must be diseased; If the father is sick, the daughter must be sick.

second: with x recessive inheritance (there is no allele on y) - characterized by more male patients than females; Cross-genetics.

The third type: Y inheritance (no allele on x) - characterized by male patients.

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