Close

2021-05-14

Why might polygenic traits vary more in phenotype than do single gene traits?

Why might polygenic traits vary more in phenotype than do single gene traits?

Why might polygenic traits vary more in phenotype than do single gene traits? Polygenic traits are controlled by two or more genes, so there are more combination of alleles leading to multiple phenotypes. Neither of the alleles block each other, so there is not true dominant recessive relationship.

How can phenotypes be used to predict genotypes in a pedigree?

Because some phenotypes that are observed are dominant genes, which would help predict what the genes would be. For example, brown eyes (B) are dominant, and blue eyes (b) are recessive. If someone had brown eyes, it could be predicted that their genotype would be BB or Bb.

What are most of the traits expressed in a person’s phenotype determined by?

A phenotype is an individual’s observable traits, such as height, eye color, and blood type. The genetic contribution to the phenotype is called the genotype. Some traits are largely determined by the genotype, while other traits are largely determined by environmental factors.

Why does the frequency of cross overs give information about the relative locations of genes?

Why does the frequency of cross-overs give information about the relative locations of genes? They were used to study linked genes, producing data that was used to create linkage maps displaying relative distance of genes.

How do you know if genes are linked?

We can see if two genes are linked, and how tightly, by using data from genetic crosses to calculate the recombination frequency. By finding recombination frequencies for many gene pairs, we can make linkage maps that show the order and relative distances of the genes on the chromosome.

What happens when genes are linked?

When genes are close together on the same chromosome, they are said to be linked. That means the alleles, or gene versions, already together on one chromosome will be inherited as a unit more frequently than not.

How many loci are linked?

two loci

How can crossing over unlink genes?

explain how crossing over can unlink genes. Linked genes do not assort independently because they are located on the same chromosome. In crossing over, a set of proteins orchestrates an exchange of corresponding segments of one maternal or paternal chromatid making portions of each chromosome different.

Why does Recombination between linked genes continue to occur?

Why does recombination between linked genes continue to occur? Recombination must occur or genes will not assort independently. C) New allele combinations are acted upon by natural selection.

What is the significance of the distance between two genes on the same chromosome?

The closer two genes were to one another on a chromosome, the greater their chance of being inherited together. In contrast, genes located farther away from one another on the same chromosome were more likely to be separated during recombination.

What is the maximum genetic distance between two genes?

CHROMOSOMAL MAPS AND MAPPING FUNCTIONS The “map unit” (1 cM) is the genetic map distance that corresponds to a recombination frequency of 1%. In large chromosomes, the cumulative map distance may be much greater than 50cM, but the maximum recombination frequency is 50%.

How does the distance between two genes affect crossover frequencies?

It follows that: • the probability of a crossover between two genes is proportional to the distance between the two genes. That is, the greater the distance between the two genes, the greater the probability that a crossover will occur between them during meiosis.

Why do linked genes not assort independently?

Explain why linked genes do not assort independently. Linked genes tend to be inherited together because they are located on the same chromosome. Map units indicate relative distance and order, not precise locations of gene. Distinguish between linked genes and sex-linked genes.

Can two genes not segregate independently?

In short, whenever two genes are linked because of their location on a chromosome, their alleles will not segregate independently during gamete formation.

What is Independent Assortment All of these genes assort independently meaning they Cannot?

Independent assortment is when all genes are assorted independently, meaning they cannot affect one another. Also, genes that are linked are not always necessarily linked together as depending on their locations from one another and crossing over during meiosis certain genes can be inherited and not others.

Do genes act independently?

Genes that are on different chromosomes (like the Y and R genes) assort independently. There are, however, gene pairs that do not assort independently. When genes are close together on a chromosome, the alleles on the same chromosome tend to be inherited as a unit more frequently than not.

What is independent assortment of genes?

The Principle of Independent Assortment describes how different genes independently separate from one another when reproductive cells develop. Meiosis is a type of cell division that reduces the number of chromosomes in a parent cell by half to produce four reproductive cells called gametes.

What is the principle of independent assortment quizlet?

The principle of independent assortment states that genes for different traits can segregate independently during the formation of gametes. Incomplete Dominance. Cases in which one allele is not completely dominant over another. Codominance. When both alleles contribute to the phenotype.

What are the principles of independent assortment?

Mendel’s law of independent assortment states that the alleles of two (or more) different genes get sorted into gametes independently of one another. In other words, the allele a gamete receives for one gene does not influence the allele received for another gene.

What is the principle of segregation quizlet?

The Law of Segregation states that the two alleles of a given gene will be separate from one another during gamete formation (meiosis).

What process produces four daughter cells?

meiosis

Why is the function of mitosis needed in development?

Mitosis is a way of making more cells that are genetically the same as the parent cell. It plays an important part in the development of embryos, and it is important for the growth and development of our bodies as well. Mitosis produces new cells, and replaces cells that are old, lost or damaged.

Are Matched Pairs meaning there are two copies?

In each somatic cell of the organism, the nucleus contains two copies of each chromosome, called homologous chromosomes. Somatic cells are sometimes referred to as “body” cells. Homologous chromosomes are matched pairs containing the same genes in identical locations along their length.