Specialized chromosomes determine sex.

Try your hand at sex determination.

HI! Let's try this problem. Dave and Dana have two boys. If they decide to have another child, will they have a boy or girl? Since they already have two boys, their next child will likely be a boy. That is incorrect. Since they already have two boys, their next child will likely be a girl. That is incorrect. The sex of the child is not dependent on the sex of the previous children. That is correct. The sex of each child is determined at the moment of conception, and depends on the contribution of male sperm carrying either an X or Y chromosome. Let's build a Punnett square and calculate the chance that this next child will be a boy or a girl. Dana will make eggs that have: one X chromosome. That is correct. one Y chromosome. That is incorrect. two X chromosomes. That is incorrect. one X or one Y chromosome. That is incorrect. two Y chromosomes. That is incorrect. Dana will make eggs that have one X chromosome. Dave will make sperm that have: one X chromosome. That is incorrect. one Y chromosome. That is incorrect. two X chromosomes. That is incorrect. one X or one Y chromosome. That is correct. two Y chromosomes. That is incorrect. Dave will make sperm that have one X or one Y chromosome. When fertilization occurs, how many will be boys and how many will be girls? All will be boys. That is incorrect. Half will be boys, half will be girls. That is correct. All will be girls. That is incorrect. There will three boys for every girl. That is incorrect. There will be three girls for every boy. That is incorrect. When fertilization occurs, half the progeny will be girls (XX) and half will be boys (XY). CONGRATULATIONS! YOU'RE SO SMART!

y chromosomes, x chromosomes, male sperm, punnett square, sex determination, fertilization, progeny, eggs, conception

  • ID: 16261
  • Source: DNALC.DNAFTB

Related Content

16249. Specialized chromosomes determine sex.

DNAFTB Concept 9: Study of meiosis revealed the chromosomal basis of sex.

  • ID: 16249
  • Source: DNALC.DNAFTB

16250. Specialized chromosomes determine sex.

DNAFTB Animation 9: Nettie Stevens and Edmund Wilson explain how biological sex is determined by special chromosomes.

  • ID: 16250
  • Source: DNALC.DNAFTB

10536. "Fig. 6. The chromosomes of man"

"Fig. 6. The chromosomes of man"

  • ID: 10536
  • Source: EA

16237. Concept 8: Sex cells have one set of chromosomes; body cells have two.

Offspring arise from the union of specialized sex cells — a female egg and a male sperm.

  • ID: 16237
  • Source: DNAFTB

16238. Sex cells have one set of chromosomes; body cells have two.

DNAFTB Animation 8: Theodor Boveri presents chromosomes' role in development.

  • ID: 16238
  • Source: DNALC.DNAFTB

16996. Genes and Inheritance

An animation introducing the basic concepts of genetics and recessive inheritance.

  • ID: 16996
  • Source: DNALC

16931. 2D Animation of Genes and Inheritance

An animation introduces DNA and the pattern of inheritance for SMA.

  • ID: 16931
  • Source: DNALC.SMA

15520. DNA is organized into 46 chromosomes including sex chromosomes, 3D animation

DNA is organized into 46 chromosomes including sex chromosomes, 3D animation

  • ID: 15520
  • Source: DNAi

15606. Y chromosome

The Y chromosome.

  • ID: 15606
  • Source: DNAi

15420. Y Chromosome: SRY gene responsible for the masculinization process, Matt Ridley

Matt Ridley talks about Y Chromosome, SRY gene responsible for the masculinization process.

  • ID: 15420
  • Source: DNAi