Chromosomes

What is independent assortment in genetics?

The principle that alleles for different traits segregate independently during gamete formation.

During which phases of meiosis does independent assortment occur?

Metaphase I and Prophase I.

Who conducted significant research on Drosophila and independent assortment?

T.H. Morgan at Columbia University in 1919.

What is a dihybrid testcross?

A genetic cross that examines the inheritance of two traits simultaneously.

What is the maximum recombinant frequency indicating independent assortment?

50% recombinant frequency.

What does a recombinant frequency of 50% signify?

It indicates that independent assortment is occurring due to 100% crossover frequency.

What is the significance of the black to vestigial map distance in Drosophila?

The map distance is 17, indicating the physical distance between the two genes on the chromosome.

What is a hemizygote?

An individual with only one copy of an allele, often referring to males with sex-linked traits.

What are sex-linked traits?

Traits that are associated with genes located on sex chromosomes.

What is the chromosomal basis for recombination of linked genes in Drosophila?

Recombination occurs during crossover events in meiosis, resulting in different combinations of alleles.

What is the role of sex chromosomes in sex determination?

Sex chromosomes determine the sex of an organism, with different systems in various species.

What is the difference between XN and Xn in terms of color blindness?

XN represents the normal allele, while Xn represents the allele for color blindness.

What is the significance of Thomas Hunt Morgan's first experiment?

It provided foundational evidence for the concept of sex-linked traits.

What is the chromosomal system of sex determination in mammals and flies?

Mammals and flies typically use an XY system for sex determination.

What is the relevance of the term 'crossover' in genetics?

Crossover refers to the exchange of genetic material between homologous chromosomes during meiosis.

What is the outcome of a dihybrid cross with complete linkage?

It results in offspring that display only the parental phenotypes.

What does a recombinant frequency of less than 50% indicate?

It suggests that the genes are linked and do not assort independently.

What is the importance of studying Drosophila in genetics?

Drosophila serves as a model organism for understanding genetic principles due to its simple genetics and rapid life cycle.

What is the significance of National Hispanic Heritage Month in relation to Kellie Jurado?

Kellie Jurado is highlighted as a first-generation college student and a notable figure in virology research.

What is the significance of map distance in genetics?

Map distance indicates the frequency of recombination between genes, with a higher percentage suggesting greater distance and likelihood of crossover.

What percentage of offspring are expected to be recombinants when genes are on the same chromosome with crossover?

34% recombinants with crossover.

What is the expected percentage of parental types when genes are on the same chromosome without crossover?

66% parental types.

In a genetic cross of 2,300 flies, how many were predicted to be black and vestigial?

Predicted 954.5, observed 944.

What does independent assortment refer to in genetics?

Independent assortment refers to the random distribution of alleles during gamete formation, especially when genes are located on different chromosomes.

What is epistasis in genetics?

Epistasis occurs when one gene masks or alters the phenotypic effects of another gene at a different locus.

What is the role of the Stay-Green gene in peas?

The Stay-Green gene is responsible for breaking down chlorophyll, with yellow being dominant to green.

What is the dominant trait for pod color in peas?

Green pod color (Gp) is dominant to yellow (gp).

What is the chromosomal location of Mendel's traits in peas?

Peas have 7 pairs of chromosomes, with specific traits located on designated chromosomes.

How does bacterial conjugation occur?

Bacterial conjugation involves the formation of a sex pilus and the transfer of genetic material between bacteria.

What are the characteristics of organelle DNA?

Organelle DNA, such as mtDNA, evolves quickly, is maternally inherited, and exists in many copies within each cell.

What is the significance of chloroplast DNA in plants?

Chloroplast DNA is inherited through seeds and plays a role in photosynthesis.

What is the expected outcome of a cross between two loci with complete dominance?

The offspring will exhibit traits based on the dominant alleles present.

What is the expected ratio of parental to recombinant types when genes are far apart on the same chromosome?

50% parental types and 50% recombinant types.

What is the role of the bHLH transcription factor in peas?

The bHLH transcription factor is involved in gene regulation and splicing errors.

How many bases are in human mitochondrial DNA?

Human mitochondrial DNA contains 16,569 bases.

What is the effect of the B and T alleles on plant height?

B and T alleles each contribute +1 inch to plant height, but their combined effect is +1.5 inches due to epistasis.

What is the expected outcome when a crossover occurs between two genes on the same chromosome?

Crossover can result in recombinant offspring, altering the expected ratios of traits.

What is the difference in chromosome number between peas and Drosophila?

Peas have 7 pairs of chromosomes, while Drosophila have 4 pairs.