How to determine if two genes are on the same chromosome

The progeny was obtained by crossing two homozygous parents with relative traits, and the gametes produced by the progeny were counted, and the ratio of the four gametes was 1:1:1:

1, then the two genes are on non-homologous chromosomes (free combination), if there are more than two and two are less, then the two genes are on homologous chromosomes (linkage exchange).

A: Two pairs of alleles located on a pair of homologous chromosomes are explained by the law of gene segregation.

1. If AB is located on one chromosome of a pair of homologous chromosomes, and AB is located on another chromosome of this pair of homologous chromosomes, they will inbreed AABB, 2AAB, and AABB. Three genotypes. If there is an additive effect on the gene, there are three phenotypes.

If the presence of A and B manifests as one phenotype, then there are two phenotypes.

2. If AB is located on one chromosome of a pair of homologous chromosomes, and AB is located on another chromosome of this pair of homologous chromosomes, they will inbreed three genotypes: AABB, 2AABB, and AABB. If only one capitalized gene is a phenotype, and there is an additive effect, they have only one phenotype. If A is a phenotype, B is another phenotype, and A, B is another phenotype.

It has three phenotypes.

Chromosomes are composed of proteins and DNA, and the gene is a fragment of the DNA molecule with genetic information, the DNA molecule is very long, and the genes are arranged on the DNA molecule in a regular manner, and there are many genes on each DNA molecule

So the answer is: ,8,

Homologous chromosomes refer to two chromosomes from the parents in a pair of chromosomes, which should be similar in length, morphology, order, etc. under normal circumstances. When the parents of an organism are both of the same species, and there are no errors in the formation of germ cells, there are usually the same genes at the same location on the homologous chromosomes.

During sexual reproduction, an organism acquires a homologous chromosome from each parent. In the process of cross-swapping, some genes on the chromosome are exchanged, which makes the genes in some regions of the homologous chromosome slightly different, but this change usually only affects the order in which the genes are arranged, not the sequence of the genes themselves.

So, in most cases, there will be the same genes at the same location on the homologous chromosomes. However, in some cases, factors such as gene mutations, genetic recombination, and gene deletions may also cause different genes at the same location on the homologous chromosome.

A homologous chromosome is a pair of chromosomes, one from the mother and the other from the father, with two chromosomes of the same length, morphology, and genetic order. When the same chromosome carries the same allele at the same locus, it is called homozygous.

There are two situations for the formation of homozygotes, one is that in the case of cross-swapping, homologous chromosomes will undergo genetic recombination, and new chromosome combinations will be formed, resulting in the emergence of different alleles. On the other hand, homologous chromosomes carry the same allele in the same position without genetic recombination.

In humans, there is a 50% chance that the same allele will be carried at the same location on the homologous chromosome, since the parents randomly pass one of their chromosomes to their offspring during reproduction. In inbreeding, self-breeding, or some special populations, the probability of carrying the same allele at the same location on homologous chromosomes may be higher due to a higher degree of genetic similarity.

Overall, the case of carrying the same allele at the same location on the homologous chromosome affects research in fields such as genetics and genomics.

Homologous chromosomes are a pair of two chromosomes with the same morphology and size, but one from the father and one from the mother, to determine whether the two pairs of genes are not on the homologous chromosome, just see if they are alleles, they are on the homologous chromosome, and vice versa.

If the combination is free in the late minus one, it is on non-homologous chromosomes.

Set two pairs of AA and BB

F1 was obtained with the dominant homozygous and recessive homozygous co-parent aabbxaabb, and then the F1 was self-inbred if 4 traits appeared in the F2 generation with a ratio of 9:3:3:

1 then the two pairs of genes are on non-homologous chromosomes, and if only two traits are bidominant and double recessive (ratio 3:1) appear, it is on homologous chromosomes.

Two pairs of genes on non-homologous chromosomes is an experiment in textbooks.

If it is on the homologous chromosome, then it can be regarded as a pair of genes, whether it is the parent or the F1 generation, the gametes they produce are only AB and AB (tied to the same chromosome can not be freely combined), the experimental process can be regarded as, DDXDD, and then F1 self-breeding, the result is of course dominant than recessive 3:1! Earl.

(human chromosomes).

In an individual, there are multiple pairs of chromosomes, and each pair of chromosomes will be different in morphology and the number of DNA species. Even for the same pair of chromosomes, the DNA will be different in morphology and morphology and number (take the X and Y chromosomes as examples, the two determine sex, and the DNA is different).

On the other hand, the type of DNA is the same between different cells of the same individual, because the genes are selectively expressed, which makes the functions of different types of cells different.

Expansion: Genetic mutations in individual cells that lead to changes in DNA will lead to different types of DNA between different cells, which are generally not considered because they are not universal.

The DNA of the same chromosome is the same in different cells of the same body, and the DNA is different on different chromosomes of the same cell (

"Genetically identical" is defined as controlling the same trait (note that it is not relative) and the deoxyribonucleotide sequence is identical.

The genes on a pair of sister chromatids are all from the replication of the same DNA molecule, and the genes on the sister chromatids are the same according to the characteristics of DNA semi-preserved replication (if they are different, they may also be due to genetic recombination caused by gene mutation or cross-swapping).

However, the genes on a sister chromatid are generally not identical.